harish-chandra research instituteanlweb/0607/main.pdf · contents 1. about the institute 1 2....

HARISH-CHANDRA RESEARCH

INSTITUTE

ACADEMIC REPORT

( 2006-07 )

Chhatnag Road , Jhunsi , Allahabad - 211 019 ,India

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CONTENTS

1. About the Institute 1

2. Director’s Report 3

3. Governing Council 9

4. Academic Staff 11

5. Administrative Staff 16

6. Academic Report - Mathematics 18

7. Academic Report - Physics 62

8. Lectures , Talks & Seminars - Mathematics 164

9. Lectures , Talks & Seminars - Physics 166

10. Colloquium Jointly Organised by Maths and Physics 171

11. Publications & Preprints - Mathematics 173

12. Publications & Preprints - Physics 179

13. About the Library 196

14. About the Computer Section 197

15. Construction Work at the Campus 199

16. Vigilance Activities at the Campus 200

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ABOUT THE INSTITUTE

THE EARLY YEARS

The Harish-Chandra Research Institute is one of the premier research institutesin the country. It is an autonomous institute fully funded by the Departmentof Atomic Energy, Government of India. Till 10th October 2000 the Institutewas known as the Mehta Research Institute of Mathematics and MathematicalPhysics (M.R.I). On 11.10.2000 it was renamed as Harish-Chandra Research Insti-tute (H.R.I) after the mathematician, late Prof. Harish-Chandra.

The Institute started with the efforts of Dr. B. N. Prasad, a mathematician at theUniversity of Allahabad, who obtained the initial support from the B. S. MehtaTrust, Kolkata. Dr. Prasad was succeeded in January 1966 by Dr. S. R. Sinha,also of Allahabad University. He was followed by Prof. P. L. Bhatnagar, whojoined as the first formal Director. On Prof. Bhatnagar’s demise in October 1976,the responsibilities were again taken up by Dr. Sinha. In January 1983, Prof. S.S. Shrikhande of Bombay University joined as the next Director of the Institute.During his tenure the dialogue with the Department of Atomic Energy (DAE)entered into the decisive stage and a review committee was constituted by theDAE for examining the future of the Institute. In 1985 N. D. Tiwari, the thenChief Minister of Uttar Pradesh, agreed to provide sufficient land for the Insti-tute and the DAE promised financial support for meeting both the recurring andnon-recurring expenditure. In January 1990, finally, about 66 acres of land wasacquired in Jhunsi, Allahabad and the institute has since came up at this site .

Prof. Shrikhande was followed by Prof. H. S. Mani who took over as the Directorin January 1992. With his joining and the shift to the new campus at Jhunsi in1996, the activities of the Institute picked up quickly. This phase of rapid growthis still continuing.

THE NEW PHASE

After a distinguished tenure of about nine years Prof. Mani retired in August2001 and the charge was taken over by Professor Ravi S. Kulkarni. After thetenure of Prof. Kulkarni, Prof. Amitava Raychaudhuri has taken over as Directorwith effect from 19.07.2005. The Institute continues to be devoted to fundamen-tal research in diverse areas of Mathematics and Theoretical Physics. Research iscarried out by about 35 faculty members, visiting faculty, post-doctoral fellows,and Ph.D. students numbering around 50. Since the year 1992 the institute has at-tracted worldwide attention, as is evident from the recognition received by manyof its faculty members, both at the national and international levels. Amongst

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them, Prof. Ashoke Sen, Prof. D. Prasad, Prof. B. Mukhopadhyaya, D. Choud-hury and Prof. Rajesh Gopakumar merit special mention. Prof. Ashoke Sen,Prof. D Prasad and Prof. B. Mukhopadhyaya are all winners of the prestigiousS.S. Bhatnagar award. Prof. Ashoke Sen was also honoured through the Pad-mashree Award, election to the Fellowship of the Royal Society, and award ofthe INSA S.N. Bose Medal and the prestigious J.C. Bose Fellowship of the Dept.of Science and Technology. Prof. I.B.S. Passi was awarded the Life-time ServiceAward by INSA, New Delhi. Prof. Rajesh Gopakumar won the SwarnajayantiFellowship of the Dept. of Science and Technology and the coveted ICTP prizefor 2006. Prof. Biswarup Mukhopadhyaya was elected a fellow of the NationalAcademy of Sciences, India. Dr. Srubabati Goswami was selected for the Dr. P.Sheel Memorial (Young Woman Scientist) Lecture award 2006 by the NationalAcademy of Sciences, India.

RESEARCH IN MATHEMATICS

The mathematics group at HRI carries out research in several areas. In algebra,we are engaged in the study of algebraic groups and related structures, the theoryof groups and group rings, representation theory, and infinite-dimensional Liealgebra. The work at HRI in analysis is in the field of harmonic analysis of Liegroups. The activity in geometry includes discontinuous groups and Riemannsurfaces, algebraic topology, variational problems on manifolds, Chow groups ofrational surfaces, and moduli of vector bundles. The number theory group workson algebraic, analytic and combinatorial number theory, automorphic forms andcryptography.

RESEARCH IN PHYSICS

At HRI, research in theoretical physics in carried out in the fields of astrophysics,condensed matter physics, high energy phenomenology and string theory. In as-trophysics, the faculty is involved in the investigation of the cosmic microwavebackground radiation, the large scale structure of the universe and the evolutionof galaxies. The main areas of activity in condensed matter physics are stronglycorrelated electron systems, mesoscopic systems, quantum Hall effect and super-conductivity. In string theory, perturbative and non-perturbative aspects of stringtheory and quantum field theory are being actively investigated. In high energyphenomenology, research is carried out in the following areas: neutrino physics,strong interactions, lattice gauge theory, supersymmetry and various aspects ofphysics beyond the standard model.

The Institute has a residential campus in Jhunsi, with a very well endowed re-search library, state of the art computational facilities and fast Internet links tothe outside world. There is an active Graduate Program and a large traffic ofvisiting scientists and students at the Institute.

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DIRECTOR’S REPORT

In 2006-07, Harish-Chandra Research Institute (HRI) has made good, consistentprogress towards its goal of achieving further excellence in the fields of mathe-matics and theoretical physics. The research and training activities of HRI haveattracted much national and international attention manifested through impor-tant publications, invitations for collaborative work, conference invitations, etc.Among prospective Ph.D. students, HRI is one of the most coveted in the coun-try. There are also many applications from outside the country for post-doctoralpositions at the Institute.

The Department of Atomic Energy (DAE), Government of India, which finan-cially supports HRI, has research in basic science as a major component of itsR&D sector. HRI is a prominent member of the group of DAE institutes and isknown for its specialised, high quality expertise. HRI is very much on the way ofsetting up closer linkages with other DAE institutions through the Homi BhabhaNational Institute (HBNI) to which all the newer Ph.D. students are enrolled.DAE has approved the Annual Plan allocation in BE 2007-08 (XIth Plan) amount-ing to a total of 18.46 Crores. Work on the different XIth Plan projects have startedin right earnest and much activity is foreseen in the year ahead.

The Institute is undergoing an External Peer Review to assess its progress andto identify directions for future development. Part I of this Review took placein February 2007 and was undertaken by a panel consisting of Professors M.S.Narasimhan (TIFR, Bangalore), Jean-Marc Deshouillers (Bordeaux, France), andJoseph Oesterle (Paris, France). It saw an unprecedented level of coordinationand cooperation between one and all at the Institute. Part II of the Review willtake place in November 2007 and a combined report on the two Reviews will besubmitted by the expert panel.

The members of the Institute have continued to win laurels from India and abroad.Let me list some of those:

• Professor Ashoke Sen was awarded the J.C. Bose fellowship of the Depart-ment of Science and Technology.

• Professor Rajesh Gopakumar was chosen for the Swarnajayanti Fellowshipof the Department of Science and Technology and also for the ICTP Prizefor 2006 by the Abdus Salam International Centre for Theoretical Physics,Trieste (Italy).

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• Dr. Srubabati Goswami was awarded the Dr. P. Sheel Memorial (YoungWoman Scientist) Lecture award of 2006 by the National Academy of Sci-ences, India. This award is made once every three years.

• Professor Biswarup Mukhopadhyaya was elected a Fellow of the NationalAcademy of Sciences, India.

The Birth Centenary of Sri Girdharilal-ji Mehta – to whose vision and generositythis Institute owes its very origin – was celebrated through a one-day programmeon December 07, 2007 organized jointly with the Bharatiya Vidya Bhavan. Thewell-attended programme was held at the Prayag Sangit Samiti auditorium inAllahabad. Professor Ram Murty of Queen’s University, Canada gave a talk on‘Logic, Number Theory, and the Limits of Human Reason’. Professor M.S. Raghu-nathan, Chairman, HRI Governing Council chaired the programme. It was a priv-ilege that Professor R. Balasubramanian, Member, HRI Governing Council, alsograced the occasion by his presence. Professor Ram Murty’s Lecture is the firstHRI Girdharilal Mehta Lecture of HRI. We expect to make this into a continuingseries and arrange more such lectures of wide interest by prominent academi-cians.

With the approval of the Council and the Building Works Committee, for a long-time discussions were continuing with the Uttar Pradesh Power CorporationLimited (UPPCL) to secure an uninterrupted 33kV power connection for HRI.I am happy to report that these discussions have now borne fruit after severalmeetings with the DGM of UPPCL and other officials. It is expected that the un-interrupted power supply will become available within the next year.

During the last year, Mr. P.B. Chakraborty has joined the Institute as Registrar.We welcome him to HRI and hope that the Institute will greatly benefit from hispast administrative experience. Mr. Chakraborty took over from Mr. M.P. Shri-vastav who served as the Acting Registrar. I would like to express my thanks toMr. M.P. Shrivastav for taking over as Acting Registrar at short notice and help-ing the Institute function smoothly in the transition phase.

Mr. R.D. Maurya retired from the Institute on 31.12.06 after serving the Institutefor several decades.

I now give a brief summary of the meetings, lectures, etc. which were held at theInstitute during 2006-07.

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• Scientific meetings:

1. HRI took the responsibility of organising the first INO Training School.It was held during 10th to 25th April 2006.

2. An international conference was held during 1st - 5th December 2006on Number Theory. About 40 participants attended the conferencefrom India and abroad.

3. An informal workshop on String Theory was organized from 7th to10th December 2006. About 15 scientists from India and abroad at-tended this workshop.

4. A Topical meeting on Physics at the LHC was held from 16th to 21stDecember 2006. For the first time at HRI, this meeting arranged a re-mote video lecture presentation when one of the invited speakers fromabroad had to change plans at the last moment.

5. An international conference on Number Theory & Cryptography washeld during 23rd - 27th February 2007. About 35 participants fromoutside and 25 from the Institute attended the conference.

• Visitors to the Institute:

Professors Soumitra Sengupta (IACS, Kolkata), D. Bhattacharjee (NEHU,Shillong), I. Baoulina (IMSc, Chennai), A.K. Mishra (IMSc, Chennai), J. K.Bhattacharjee (IACS, Kolkata), K. Subramanian (IUCAA, Pune), Kamal Datta(Delhi University), Somdatta Sinha (CCMB, Hyderabad), Roy Joshua (OhioUniversity, USA), W. Krawcewicz (University of Alberta, Canada), OttoKong (National Central University, Taiwan), N.P. Skoruppa (University ofSiegen, Germany), A. Gopakumar (Theor. Phys. Institut, Jena, Germany),K. Narayan (TIFR, Mumbai), Jayajit Das (MIT, Mumbai), D. Prasad (TIFR,Mumbai), K. Varadarajan (University of Calgary, Canada), R. Nityananda(NCRA, Pune), S. Loktev (ITEP, Moscow), Arunansu Sil (Saclay, France),Niklas Beisert (Albert Einstein Institute, Potsdam), Maury Goodman (Ar-gonne National Lab, USA), Arijit Bhattacharya (University of Padova, Italy),Debaprasad Maity (IACS, Kolkata), Hidekazu Furusho (Nagoya Univer-sity), Subir K. Das (University of Maryland, USA), T. Roychoudhury (CTS,IIT Kharagpur), Basudeb Datta (IISc, Bangalore), Henri Darman (McGillUniversity, Canada), T. Senthil (IISc, Bangalore) and T. N. Shorey (TIFR,Mumbai) were among the visitors to the Institute.

• HRI Girdharilal Mehta Lecture:

1. Professor Ram Murty: 07.01.07 – Logic, Number Theory, and the Limitsof Human Reason

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2. Professor Joseph Oesterle: 19.03.07 – Why do Antennas emit Waves?

• HRI Colloquia:

1. J.K. Bhattacharjee: 10.4.06 – Divergent Critical Viscosity: Convergent The-ory and Experience.

2. K. Subramanian: 21.4.06 – Magneto-Genesis in the Universe.

3. Kamal Datta: 27.4.06 – Einstein, Classical and Modern: Atomism, Rela-tivity and Quantum Mechanics.

4. Somdatta Sinha: 16.5.06 – Modelling Biological Systems.

5. Ram Ramaswamy: 18.9.2006 – Finding genes (and other things) in DNAsequences: Mathematical methods for genomic analysis.

6. Tarun Souradeep: 27.10.2006 – Celebrating the Cosmic Microwave Back-ground.

7. Swara Ravindranath: 6.11.2006 – Observational Constraints on GalaxyFormation from Deep Surveys.

8. Nils-Peter Skoruppa: 27.11.2006 – On the Physics of the Rogers-RamanujanIdentities.

9. Yuval Gefen: 4.12.206 – How to measure a fractional statistical phase.

10. T. Senthil: 6.12.2006 – Quantum criticality beyond the Landau-Ginzburg-Wilson paradigm.

11. Debashish Chowdhury: 11.12.2006 – Interacting self-propelled particles:from molecules to vehicles.

12. Gyan Bhanot: 22.12.2006 – Inferring Common Origins: How clusteringand principal component analysis reveal the migration history of humansout of Africa.

13. Maury Goodman: 22.12007 – The Neutrino Oscillation Industry.

• Physics Colloquia:

1. A. Gopakumar: 29.1.2007 – Gravitational Wave Astronomy.

• Lecture Series:

1. Dr. Ioulia Baoulina, IMSc, Chennai, visited during 8.4.06 to 7.5.06 andgave a lecture On diagonal equations over finite fields.

2. Dr. A.K. Mishra, IMSc, Chennai, visited during 16.4.06 to 1.5.06 andgave two lectures on Metal-Insulator transition in an adsorbed layer atan Electrochemical interface and Ortho-fermi Quantum Statistics andits applications to the Infinite-U Hubbard Model.

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3. Prof. Soumitra Sengupta, IACS, Kolkata, visited during 26.5.06 to 2.6.06and delivered a lecture on Stability and Hierarchy Problems in a Back-reacted Randall-Sundrum braneworld.

4. Professor Peter West, King’s College, London, visited during 19.9.06to 3.10.06 and delivered a lecture series on E11 and the Symmetries ofM-Theory.

5. Professor T.N. Shorey, TIFR, Mumbai, visited during 6.11.06 to 8.12.06and delivered a lecture series on Linear forms in logarithms and itsapplications.

6. Professor Roy Joshua, Ohio University, USA, visited during 4.1.07 to21.1.07 and delivered a lecture series on Etale Cohomology.

7. Professor W. Krawcewicz, Univ. of Alberta, Edmonton, Alberta, Canada,visited during 12.1.07 to 19.1.07 and delivered a lecture series on Equiv-arient Degree and its applications.

8. Professor Otto Kong, National Central University Taipei, Taiwan, vis-ited during 20.1.07 to 25.1.07 and delivered a lecture on Towards thetheory of Special Quantum Relativity.

9. Professor S.T. Petcov, SISSA, Trieste, Italy visited during 21.1.07 to 24.1.07and delivered a lecture on Leptogenesis and Low Energy CP-Violationin the Lepton Sector.

10. Professor Werner Rodejohann, Max-Planck-Instiute fur Kernphysik, Ger-many visited during 21.1.07 to 24.1.07 and delivered a lecture on Struc-ture of Neutrino Mixing and Quark-Lepton Complementarity.

11. Professor J. Oesterle, Institut Henri Poincare, Universite Paris VI, France,visited during 2.2.07 to 2.4.07and delivered a series of ten lectures onModuli space of genus zero curves with n marked points.

• Other Activities and Events:

1. Like other years, the Visiting Students’ Summer Programme (VSSP) forB.Sc. and M.Sc. students was organised in 2006. The Mathematics VSSPwas held during June 07 – 23, 2006. The Physics VSSP was also conducetdduring the summer in which students attended the program in batches.

2. Founder’s Day : Founder’s Day was celebrated on 19th July 2006. Mr.Amrit Abhijat, IAS, District Magistrate, Allahabad was the Chief Guest.Professor R.G. Harshe, Vice-Chancellor, University of Allahabad was theGuest of Honour. Professor Harshe delivered a popular talk on “Globaliza-tion in India”. A Kavya Gosthi was also arranged on this occasion.

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3. Rajbhasha programme was organized on 19th September 2006 for thechildren of staff members.

4. NBHM : Written test for NBHM scholarships was conducted on 23rdSeptember and the interviews were held on 2nd November 2006.

5. Science Talent Search : Written test for school children (9th to 12th class)was organized on 11th November 2006.

6. Science Talent Search award function was held on 25th January 2007.

7. NBHM : Written test was held on 27th January 2007 for admission to theInstitute’s Ph.D. programme. Interviews were arranged on 16th and 17thMarch 2007, for which 10 candidates were selected.

8. JEST (Physics) : Written test was held on 18th February, 2007.

A. RAYCHAUDHURIDIRECTOR

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GOVERNING COUNCIL

1. Prof. M.S. Raghunathan School of Mathematics(Chairman) Tata Institute of Fundamental Research

Homi Bhabha RoadMumbai - 400 005

2. Mr. S.L. Mehta 4, Clive Row(Vice Chairman) Kolkata - 700 001

3. Dr. C.V. Ananda Bose, IAS Joint Secretary (R& D)(Member) Govt. of India, DAE

Chhatrapati Shivaji Maharaj MargMumbai - 400 001

4. Mr. Rahul Asthana, IAS Joint Secretary (F)(Member) Govt. of India, DAE

Chhatrapati Shivaji Maharaj MargMumbai - 400 001

5. Mr. Rama Kant Mishra IAS (Retd.)(Member) 23/1E, P.C. Banerjee Road

Allen GanjAllahabad 211 002

6. Mr. Avnish Mehta 4 Penn Road(Member) Kolkata - 700 027

7. Prof. R. Balasubramanian Director(Member) Institute of Mathematical Sciences

CIT Campus, TaramaniChennai - 600 113

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8. Dr. J.N. De Saha Institute of Nuclear Physics(Member) 1/AF, Bidhannagar

Kolkata - 700 064

9. Prof. Narendra Kumar Raman Research Institute(Member) C.V. Raman Avenue, Sadashivanagar

Bangalore 560080

10. Prof. H.S. Mani Visiting Professor(Member) Institute of Mathematical Seiences

CIT Campus, TaramaniChennai - 600 113

11. Dr. Miyan Jan Director of Higher Education(Member) Uttar Pradesh

Allahabad - 211 001

12. Prof. Amitava Raychaudhuri Director(Ex-Officio Member) Harish-Chandra Research Institute

Allahabad - 211 019

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ACADEMIC STAFF

Faculty Members (Mathematics)

1. Prof. Sukumar Das Adhikari

2. Dr. Punita Batra

3. Dr. Kalyan Chakraborty

4. Dr. C. S. Dalawat

5. Dr. Rukmini Dey

6. Dr. Ratnakumar P. K.

7. Dr. N. Raghavendra

8. Prof. B. Ramakrishnan

9. Dr. D. Surya Ramana

10. Dr. R. Thangadurai

Visiting Professor (Mathematics)

1. Prof. S. D. Tripathi

Visiting Scientist (Mathematics)

1. Dr. Manoj Kumar

2. Dr. Amora Nongkynrih

Visiting Fellow (Mathematics)

1. Dr. Rabeya Basu

2. Dr. Tarakant Nayak

3. Dr. Prabal Paul

4. Dr. Gyan Prakash

5. Dr. Ritumoni Sarma

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Research Scholar (Mathematics)

1. Mr. Sanjay Kumar H. Amrutiya

2. Mr. V. V. Awasthi

3. Mr. Mohan Namdev Chintamani

4. Mr. Soumya Das

5. Mr. Ratnesh Dixit

6. Mr. Krishnendu Gangopadhyaya

7. Mr. Moriya Bhavin K.

8. Mr. Jaban Meher

9. Ms. Archana S. Morye

10. Ms. Tanusree Pal

11. Ms. Anupama Panigrahi

12. Ms. Supriya A. Pisolkar

13. Mr. Brundaban Sahu

14. Mr. Karam Deo Shankhadhar

15. Mr. Mahender Singh

16. Mr. Mahendra Kumar Verma

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Faculty Members (Physics)

1. Prof. J. S. Bagla

2. Dr. Sandhya Choubey

3. Prof. Debajyoti Choudhury (on leave)

4. Dr. Tapas Kumar Das

5. Dr. Anindya Datta (on leave)

6. Dr. Asesh K. Datta

7. Dr. Justin R. David

8. Prof. Raj Gandhi

9. Prof. Debashis Ghoshal

10. Prof. Rajesh Gopakumar

11. Dr. Manoj Gopalakrishnan

12. Dr. Srubabati Goswami

13. Prof. Dileep Jatkar

14. Prof. Pinaki Majumdar

15. Prof. Biswarup Mukhopadhyaya

16. Prof. Satchitananda Naik

17. Prof. Sudhakar Panda

18. Dr. T. P. Pareek

19. Prof. Sumathi Rao

20. Prof. V. Ravindran

21. Prof. Ashoke Sen

22. Dr. Prasenjit Sen

23. Dr. L. Sriramkumar

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Visiting Professor (Physics)

1. Prof. Mina Ketan Parida

Visiting Scientist (Physics)

1. Dr. Paramita Dey

2. Dr. Bindu Govindan

3. Dr. H. K. Jassal

4. Dr. Andreas Nyffeler

Visiting Fellow (Physics)

1. Dr. S. S. Deshingkar

2. Dr. Theodre G. Erler

3. Dr. Jinn-Ouk Gong

4. Dr. Prabuddha Sanyal

Research Scholar (Physics)

1. Mr. Sanjib Kumar Agarwalla

2. Mr. Arjun Bagchi

3. Mr. Priyotosh Bandyopadhyay

4. Ms. Nabamita Banerjee

5. Mr. Shamik Banerjee

6. Mr. Subhaditya Bhattacharya

7. Mr. Sanjoy Biswas

8. Mr. Turbasu Biswas

9. Mr. Joydeep Chakraborty

10. Ms. Nishita D. Desai

11. Mr. Anindya Dey

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12. Mr. Suvankar Dutta

13. Ms. Pomita Ghoshal

14. Mr. Rajesh Kumar Gupta

15. Mr. Sudhir Kumar Gupta

16. Mr. Dhiraj Hazra

17. Mr. R. Srikanth H.

18. Mr. Rajeev Kumar Jain

19. Mr. Nishikanta Khandai

20. Mr. Girish P. Kulkarni

21. Mr. Shailesh Lal

22. Mr. Swarup Kumar Majee

23. Ms. Ipsita Mandal

24. Ms. Manimala Mitra

25. Mr. Anamitra Mukherjee

26. Mr. Ayan Mukhopadhyay

27. Mr. Satyanarayan Mukhopadhyay

28. Mr. Kalpataru Pradhan

29. Mr. Jayanti Prasad

30. Mr. Arijit Saha

31. Mr. Bindusar Sahoo

32. Mr. Shashank M. Shalgar

33. Mr. Viveka Nand Singh

34. Mr. Santosh Kumar Swain

35. Mr. Rajarshi Tiwari

36. Mr. Anurag Tripathi

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ADMINISTRATIVE STAFF

1. Shri P.B. Chakraborty Registrar (from 05.07.06)2. Shri Raaj Kumar Gulati Accounts Officer3. Shri V. R. Tiwari Librarian4. Shri Prabhat Kumar Senior Private Secretary5. Shri Amit Roy Internal Audit cum Admn. Officer6. Shri K.S. Shukla Professional Assistant7. Shri Jagannath Yadav Accountant8. Shri R. P. Sharma Guest House Manager9. Dr. Archana Tandon Office Superintendent10. Shri Deepak Srivastava Store Purchase Officer11. Shri V. P. Tiwari Jr. Hindi Translator12. Shri Uma Kant Dwivedi Cashier13. Shri D. Malhotra UDC14. Shri K. K. Srivastava UDC15. Shri Yashpal Singh Steno16. Mrs Sumitra UDC17. Shri Parmanand Mishra Jr. Library Assistant18. Shri Dharm Pal Sharma Jr. Library Assistant19. Mrs Seema Agarwal Receptionist20. Shri Jitendra Sinha Hindi Typist21. Shri Kashi Prasad Driver22. Shri Dina Nath Dubey Bearer (Canteen Cadre)23. Shri Lalloo Ram Bearer (Canteen Cadre)24. Shri Kamlesh Thakur Bearer (Canteen Cadre)25. Shri Ramakant Dixit Watchman/Peon26. Shri Kamta Prasad Watchman/Peon27. Shri Rajesh Kumar Sweeper28. Shri Munna Lal Gardener

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Engineering/Technical Staff:

1. Shri Manish Sharma Scientific Officer ’C’2. Shri Sanjai Verma Systems Manager3. Ms. Anju Verma Scientific Asstt.4. Shri Ajay Kumar Srivastava Jr. Engineer (Electrical)5. Shri V. K. Srivastava Jr. Engineer (Civil)

Medical Consultants/Pharmacists:

1. Dr. G. S. Sinha Authorised Medical Consultant2. Dr. Bharat Arora Emergency Medical Officer3. Dr. Md. Osama Jafri Emergency Medical Officer4. Dr. Nidhi Mishra Emergency Medical Officer5. Dr. S. D. Pandey Emergency Medical Officer6. Dr. Rakesh Verma Emergency Medical Officer7. Shri S. R. Gautam Sr. Pharmacist8. Shri Piyush Dixit Pharmacist9. Shri Alok Pandey Pharmacist10. Miss Shilpi Srivastava Pharmacist

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ACADEMIC REPORT - MATHEMATICS

Sukumar Das Adhikari

Research Summary:

For the particular group Z/nZ, certain weighted generalizations of some combi-natorial group invariants were considered in some joint work with Y. G. Chen, J.B. Friedlander, S. V. Konyagin and F. Pappalardi and later with Purusottam Rath.Recently, in the joint work with Purusottam Rath, values of some of these con-stants were determined in special cases. These were further generalized in a jointwork with Y. G. Chen where expected relations between these constants wereestablished under certain conditions. These investigations were followed up inanother recent work with R. Balasubramanian, F. Pappalardi and P. Rath.

Publications:

1. Sukumar Das Adhikari and Purusottam Rath, Davenport constant with weightsand some related questions Integers, 6 paper A 30, (2006).

2. S. D. Adhikari and Y. G. Chen, Davenport constant with weights and some re-lated questions - II, J. Combinatorial Theory, Ser. A, doi: 10.1016/j.jcta.2007.03.004(2007).

3. Sukumar Das Adhikari and Purusottam Rath, Zero-sum problems in combina-torial number theory, The Riemann Zeta Function and Related Themes: Pa-pers in Honour of Professor K. Ramachandra, Proceedings of internationalconf. held at National Institute of Advanced Studies (Bangalore, 13-15 De-cember 2003), (Eds. by R. Balasubramanian and K. Srinivas), RamanujanMathematical Society Lecture Notes Series, Number 2, 1– 14, (2006).

4. S. D. Adhikari, R. Balasubramanian, F. Pappalardi and P. Rath, Some zero-sum constants with weights, Proc. Indian Acad. Sci. (Math. Sci.), to appear.

5. Sukumar Das Adhikari, Stephan Baier and Purusottam Rath, An extremalproblem in lattice point combinatorics, Diophantine Equations, N. Saradha Ed.,Tata Institute of Fundamental Research, to appear.

6. S. D. Adhikari, R. Balasubramanian and P. Rath, Some combinatorial group in-variants and their generalizations with weights, CRM Proceedings and LectureNotes, Granville, Nathanson, Solymosi Eds., to appear.

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Conference/Workshops Attended:

1. Workshop on Additive Combinatorics, Centre de recherches mathematiques,Universite de Montreal, Canada, April 2006.

2. Arithmetique et Combinatoire, Saint-Etienne, France, June 2006.

3. Mathematical Foundations of Coding, Complexity, Computation and Cryptogra-phy, Indian Institute of Sciences, Bangalore, India, July 2006.

4. International Conference on Number Theory and Applications, Ramakrishna Mis-sion Vivekananda College, Chennai, India, December 2006.

5. Sesquicentennial Symposium in Mathematics of Mumbai University, Mumbai,India, January, 2007.

Visits to other Institutes:

1. Centre de Recherches Mathematiques, Universite de Montreal, Canada, April2006.

2. Laboratoire de Mathematiques de l’Universite de Saint-Etienne, France, June2006.

3. The Institute of Mathematical Sciences, Chennai, India, July 2006.

4. Indian Institute of Sciences, Bangalore, India, July 2006.

5. Department of Mathematics, Panjab University, Chandigarh, India, Novem-ber 2006.

6. The Institute of Mathematical Sciences, Chennai, India, January 2007.

7. Belur Vidyamandir, India, March 2007.

8. Indian Statistical Institute, Calcutta, India, March 2007.

Invited Lectures/Seminars:

1. Arithmetique et Combinatoire, Saint-Etienne, France, June 2006.

2. Mathematical Foundations of Coding, Complexity, Computation and Cryptogra-phy, Indian Institute of Sciences, Bangalore, India, July 2006.

3. International Conference on Number Theory and Applications, Ramakrishna Mis-sion Vivekananda College, Chennai, India, December 2006.

19

4. Sesquicentennial Symposium in Mathematics of Mumbai University, Mumbai,India, January, 2007.

Other Activities:

1. Was one of members of the organizing committee of the HRI Number The-ory Year which started in August 2006.

2. Was one of the coordinators of the International Conference on NumberTheory and Cryptography held at HRI during February 23-27, 2007.

3. Gave a course on Algebra to first year students and supervised two secondyear projects.

4. Supervised Ph. D. work of Dr. Purusottam Rath who obtained his Ph. D.degree in 2007.

· · ·

20

Rabeya Basu

Research Summary:

Recently (2000-2003), A. Bak and G. Tang studied the stabilization problems forhermitian and quadratic groups. It has been shown that one can generalize ourresults that normality is equivalent to the Local-Global Principle for the unitaryrings. I am also trying to generalise related problems for for the quadratic mod-ules with absolute stable range condition.


1. Visited Stat-Math unit, Indian Statistical Institute from March 19 to March30, 2007.

· · ·

21

Punita Batra

Research Summary:

I finished the problem of classification of irreducible, integrable representationsof graded multi-loop Lie algebras. This is a joint work of mine with Tanusree Pal.

Let Cq = C[t±11 , t±1

2 ...t±1n ], where titj = qijtjti and qij are roots of unity, be the

Quantum torus. Let DerCq be the set of all derivations of Cq. This is a Lie algebra.I am trying to find the irreducible modules of the Lie algebra Cq ∝ DerCq. I amtrying to prove the results that any irreducible Cq ∝ DerCq -module with finitedimensional weight spaces with respect to Cartan subalgebra has to be of theform V ∝ Cq, where V is a module for the Lie algebra gln.

Preprints:

1. Tanusree Pal, Punita Batra Irreducible integrable representations of graded multiloop Lie Algebras, http://arxiv.org/abs/0706.0448v1


1. Attended Chandigarh Symposium in Mathematics in memory of Prof. I. S. Luthar,at Panjab University, Chandigarh, March 2- March 3, 2007.


1. Gave an invited talk on “Integrable representations of twisted Toroidal Lie alge-bras”, in the Chandigarh Symposium in Mathematics in memory of Prof. I.S. Luthar, Panjab University, Chandigarh, March 3, 2007.

Other Activities:

1. Guiding one HRI student towards her PhD.

2. Gave two lectures in the Rajbhasha scientific workshop at HRI in May 2006.

· · ·

22

Kalyan Chakraborty

Research Summary:

During 2006 - 2007, I have been working mainly on the following areas:

1. Divisibility and non-divisibility of class numbers of quadratic number fieldsand function fields over finite fields.

2. Divisibility and non-divisibility of the order of the Tate - Shafarevich groupof elliptic curves.

3. Hilbert modular forms.

Publications:

1. Kalyan Chakraborty, Florian Luca and Anirban Mukhopadhyay, Exponentsof class groups of real quadratic fields, International Journal Of Number Theory,To Appear, (2007)

2. Kalyan Chakraborty On the Diophantine equation x+y+z = xyz = 1 , AnnalesUniv. Sci. Budapest. Sect. Comp., 27, To Appear, (2007)

Preprints:

1. Kalyan Chakraborty, Florian Luca and Anirban Mukhopadhyay, Class num-bers of number fields with many distinct prime factors, (Preprint).


1. IMSC, Chennai, India, September, 2006.

2. University of Burdwan, India, January, 2006.

3. University of Mumbai, India, January, 2006.

4. North - West University, Xian, China, March, 2007.


1. Lectured at India - UK Number Theory Conference IMSC, Chennai, September,2006.

23

2. Lectured at Conference in Number Theory and Application, Ramakrishna Mis-sion Vivekananda College, Chennai, January, 2007.

3. Lectured at ”Mathematics and Applications - Recent Trends (Mart - 2007)” , Bur-dwan University, Burdwan, India, January, 2007.

4. Lectured at Number Theory Session of the ”National Symposium”, University ofMumbai, Mumbai, India, January 2007.

5. Lectured at North - West Number Theory Conference, Weinan Teachers Collegeand University, Weinan, China, March, 2007.

Other Activities:

1. Mentoring project students:

2. Teaching & Lecture Course:

(a) Taught ‘Algebra I’ at HRI graduate school (Aug. - Dec.) in 2006.

(b) A lecture course on Arithmetic of Finite Feids, at VSSP ’06

3. Reviewing papers:

Served as the referee for Indian Journal of Pure and Applied Mathemat-

ics.

4. HRI Internal Duty:

(a) Responsible in organising NBHM written tests and interviews.

(b) Organising Summer Programme in Mathematics (SPIM), 2007.

(c) Serving as a member in the Security Committee.

(d) Serving as convener of the Sports and Entertainment Committee.

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24

Chandan Singh Dalawat

Research Summary:

The Stickelberger-Hensel congruence on discriminants was extended to the rel-ative situation, thereby sharpening the results of Frohlich. By analogy, it wasshown that discriminants of elliptic curves over local fields do not satisfy anysuch congruence condition.

For a finite extensionK of Qp, specified the Fl-line inK×/K×l which corresponds,via Kummer theory, to the unramified degree-l extension of K when K× has anelement of prime order l. This turned out to be the local counterpart of results ofHecke, which are immediate corollaries.

Introduced the notion of the idelic discriminant for elliptic curves E|K over num-ber fields — which turned out to have been anticipated by Silverman —, follow-ing Frohlich who treated extensions L|K of number fields, and found a criterionfor a given K-basis of L, or a given weierstrassian cubic defining E|K, to be ev-erywhere locally minimal.

Publications:

1. Congruent numbers, elliptic curves, and the passage from the local to the global,to appear in the Proceeding of the Ramanujan Mathematical Society work-shop, Hyderabad, 3–5 July 2005.

Conferences/Workshops Attended:

1. Recent developments in the arithmetic of Shimura varieties and Arakelov geometry,Barcelona, 10–15 July, 2006.

2. Autour des motifs, Bures-sur-Yvette, 17–30 July, 2006.

3. International conference on Arithmetic Algebraic Geometry, El Escorial, 4–8 Septem-ber, 2006.

4. Indo-UK conference on Number Theory, Madras, 18–23 September, 2006.

5. p-adic Arithmetic Geometry, Kyoto, 20–22 November, 2006.

25


1. Tata Institute of Fundamental Research, Bombay, 25–30 June, 2006.

2. Institut des Hautes Etudes scientifiques, Bures-sur-Yvette, 1–8 August, 2006.

3. Research Institute for Mathematical Sciences, Kyoto, 8–24 November, 2006.

4. Indian Statistical Institute, Bangalore, 4–11 February, 2007.


1. Congruent numbers, Visiting students’ summer programme, Allahabad, 12June 2006; Visiting students’ research programme, Bombay, 27 June 2006;Ramanujan mathematical society workshop, Hyderabad, 3–5 July, 2006; Harish-Chandra’s birthday celebration, Allahabad, 11 October 2006.

2. Basic arithmetic,Ramanujan mathematical society workshop, Hyderabad, 3–5 July, 2006.

3. Congruent numbers and the passage from the local to the global, Colloquium atthe Indian Statistical Institute, Bangalore, 6 February 2007; Colloquium atthe Indian Institute of Science, Bangalore, 9 February 2007.

4. Discriminants, Harish-Chandra research institute, Allahabad, 21 March, 2007.

Other Activities:Supervised a summer student who studied Tate’s computation of K2(Q). Dis-cussed discriminants and local fields with a post-doctoral fellow from Bombay.· · ·

26

Satya Deo

Research Summary:I continue to work in two areas of algebraic topology; (i) Cohomology Theory ofGroup Actions and (ii) Mapping Class Groups of nonmetrizable manifolds. Mymain interest has been the cohomological study of the group actions on finitisticspaces. These include various generalizations of Smith theorems on the coho-mology structure of fixed point sets and Floyd’s theorem on acyclicity of orbitspaces.

Publications:

1. Satya Deo and J.K.Maitra Freeness of homogenized spline module from a divideddomain to a subdivided domain, Frontiers in Interpolation and ApproximationEditor, N.K.Govil et al, Francis and Taylor, (2006)

2. Satya Deo and J.K.Maitra, Hilbert Series of free spline modules, Journal of In-dian Math Soc 73, page number, (2006)

3. Satya Deo, Algebraic Topology- a Primer, TRIM Series of Hindustan BookAgency, New Delhi, IInd Edition, 2006

Preprints:

1. Satya Deo, David Gauld and Mathiew Baillif, Mapping Class Groups of somenonmetrizable manifolds,

2. Satya Deo and V.V.Awasthi, Homology and Dimension -further pathological ex-amples

3. Satya Deo and K. Varadarajan A note on Weakly Co-hopfian and generalizedHopfian modules


1. International Congress of Mathematicians, Madrid, Spain, Aug 2006.

2. Annual Conference of Indian Mathematical Society, Jabalpur, December 2006.

3. Annual Conference of Bharat Ganit Parishad, Lucknow, November 2006.

27


1. University of Poona, Pune, for lectures in a Refresher Course in Mathemat-ics, December 2006,

2. University of Arkansas, Fayetteville, AR, USA Jan 9-March 31, 2007


1. Three lectures on ”An introduction to Algebraic Topology”, University of Poona,Pune, Dec 2006.

2. Six lectures on ”Homology of Group Actions”, Topology Seminar, University ofArkansas, USA, Spring 2007.

3. Two lectures on ”Homology and Dimension”, University of Poona, Pune, Dec2006.

4. Story of Poincare Conjecture- Ricci Flow University of Lucknow, Annual con-ference of Bharat Ganit Parishad, Nov 2006.

5. Maping Class Groups of nonmetrizable manifolds, IMS Annual conference atJabalpur, Dec 2006.

6. Mathematical Concepts and Fellowship Competitions in Mathematics, Dept ofMathematics, University of Allahabad, Oct 2006.

Other Activities:

1. Organized a Symposium on ”Recent Trends in Topology” during the annualconference of IMS at Jabalpur, Dec 2006.

2. Organized a series of Seminars at HRI on different topics by K.Varadarajan(University of Calgary), Ramji Lal (University of Allahabad) and John Ryan(University of Arkansas, USA) during the year of report.

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28

Rukmini Dey

Research Summary:I worked out the geometric prequantization of the vortex moduli space and theHitchin systems. The first turns out to have a family of symplectic structuresand the second a hyperKahler structure. I could geometrically prequantize thesestructures. It remains to be seen if these come from some Conformal Field theo-ries.

I have been working on a geometry problem to do with existence of ConstantMean curvature surfaces spanning several curves.

I have also been working on a topology problem to do with generalizing Neilsenfixed point theory using fiber bundles instead of universal covering space theory

Publications:

1. Rukmini Dey Geometric quantization of the moduli space of the self-duality equa-tions on a Riemann surface

Reports on Mathematical Physics Vol. 57 no. 2, pg. 179-188 (2006)

math-phy/0605026

2. Rukmini Dey Geometric prequantization of the moduli space of the vortex equa-tions on a Riemann surface

Journal of Mathematical Physics, vol. 47, issue 10, page 103501

math-phy/0605025

Preprints:

1. Rukmini Dey, HyperKahler prequantization of the Hitchin systems and Chern-Simons gauge theory with complex gauge group (in preparation, draft in math-phy/06050270)


1. New Developments in the geometry and physics of Gromov-Witten theory, MSRI,USA, May, 2006.


1. MSRI, Berkeley, USA, May 2006

29

2. University of Harvard, place, USA, April, 2006

3. University of California at Los Angeles, USA, May 2006

4. TIFR, Mumbai, India, June 2006


1. Geometric quantization of the hyperKahler structure of the Hitchin system and thevortex moduli space, MSRI, USA, Berkeley May, 2006.

2. same talk, University of Harvard, Cambridge, USA, April, 2006.

3. same talk, UCLA, California, USA, May 2006.

4. same talk, TIFR, Mumbai,India, June 2006.

Other Activities:

1. Looking after the running of a school for underpriviledged children on cam-pus

2. As a member of the Worker’s Contract Committee and as a part of the min-imum wage team, I am working towards getting minimum wage for every-one working in the campus premises.

· · ·

30

Ratnakumar Peetta Kandy

Research Summary:I have been continuing my work on regularity property of solutions to Schrodingerequation (i∂t − L)u = 0 associated to a general second order operator L. Onesuch result is a Strichartz type estimate, established for the special hermite oper-ator L = −∆ + 1

4|z|2 + i

∑nj=1 xj∂yj − yj∂xj ) on Cn which may be considered as

a prototype for Schrodinger operator with a magnetic potential and a scalar po-tential. This work is submitted for publication. This result has been extended toSchrodinger equation associated to a wide class of differential operators L withdiscrete spectrum. This preprint is in preparation.

Apart from this I am also studying the geometry of rank one symmetric spaces.In a joint work with Dr. Ritumoni Sarma, we have established a cosine formulafor the geometry of the rank one symmetric spaces of exceptional type. Such aformula is crucial in the establishing the “restricted weak type” inequality for thespherical maximal operator on symmetric spaces which is not known for sym-metric spaces of exceptional type. This preprint is in preparation.

Preprints:

1. Ratnakumar P.K., On Schrodinger propagator for the special hermite operator,preprint, (submitted for publication)

2. Ratnakumar P.K., On Schrodinger propagator for differential operators with dis-crete spectrum, (in preparation)

3. Ratnakumar P.K., Ritumoni Sarma, A cosine formula for the geometry of rankone symmetric spaces, (in preparation)


1. Harmonic and Geometric Analysis with Applications to Partial Differential Equa-tions, Spain, August, 2006

2. International Congress of Mathematicians, Spain, August, 2006

3. Conference on Harmonic and Functional Analysis, India, Dec, 2006

4. Modern Analysis and Allied Areas, India, February, 2007.

31


1. Indian Institute of Technology Kanpur, Kanpur, India, Dec 2006,

2. Banaras Hindu University, Varanasi, India, February 2007.


1. On Schrodinger propagator for a class of differential operators with discrete spec-trum, Conference on Harmonic and Functional Analysis, IIT Kanpur, Kan-pur, December 2006.

2. On Schrodinger propagator for differential operators with discrete spectrum, Mod-ern Analysis and Allied Areas, Banaras Hindu University, Varanasi, Febru-ary 2007.

Other Activities:

1. Organised Visiting Students Study Programme (Mathematics) at HRI, June,2006.

2. Gave a course on Real Analysis to Ist semester Ph.D. Students.

· · ·

32

Tarakanta Nayak

Research Summary:During 1st April’06 to 31st March’07, I have been working on the iteration of tran-scendental meromorphic functions with one completely invariant Fatou compo-nent.


1. International Conference on Number Theory and Cryptography held at HRI Al-lahabad, India, February 23-27 2007

· · ·

33

Gyan Prakash

Research Summary:

A subset of an abelian group is said to be sum-free if the sum of any pair ofelements of this subset lies in the complement of this subset. In the study ofsum-free subsets of finite abelian groups, it turns out to be convenient to classifythe groups according to the residue classes of the primes dividing their ordersmodulo 3. A finite abelian group is called type III when all the divisors of theorder of G are congruent to 1 modulo 3. In earlier work with R. Balasubramanianwe had obtained a classification theorem for largest sum-free subsets of type III.Using this in a work with D.S. Ramana we had obtained a formula for the numberof orbits of L, the set of all largest sum-free subsets of G, when G is of type III.

In a joint work in preparation with R. Balasubramanian and D.S. Ramana titledSum-free Subsets of Finite Abelian groups of Type III we describe the work mentionedabove and give a further application of the classification theorem. More precisely,for a finite abelian groupH let S(k, l, H) denote the set {B ⊂ H : |B| = k, |B+B| =l}, where B + B is the set of sums {x + y|(x, y) ∈ B × B}. The aforementionedclassification theorem enables us to obtain a relation between the cardinality ofthe set SF (G), where SF (G) is the set of all sum-free subsets of G, and that ofS(k, l, H), where H is a supplement of a copy of Z/mZ in G with m being theexponent of G. These results are obtained by refining the methods developedby Ben Green and Imre Ruzsa (Israel J. Math., Vol. 147, 2005) for the study ofsum-free subsets in finite abelian groups.

When G is the additive group of a finite dimensional vector space over a finitefield, we improve the estimate for S(k, l, G) provided by Ben Green (Combinator-ica, Vol. 25, 2005). This, together with the results mentioned above, then allowsus to obtain a substantial improvement for the upper bound of the cardinality ofSF (G), when G = (Z/pZ)r with p being a prime congruent to 1 modulo 3. Thework in preparation mentioned above ends with an account of this improvement.

A finite subset of an abelian group is said to be incomplete if there is an element inG which can not be written as a sum of distinct elements from G and is zero-freeif the identity element of G is such an element. In a preprint authored togetherwith Jean-Marc Deshouillers titled Large zero-free and incomplete subsets of Z/pZ,we study the structure of zero-free and incomplete subsets of Z/pZ the cardinalityof which is close to largest possible, when p is sufficiently large a prime. In anearlier work, recorded in the same preprint, we had determined the cardinalityof the largest zero-free subset of Z/pZ, when p is sufficiently large a prime.

An important requirement in the context of inequalities of the large sieve type is

34

to obtain estimates for the sum∑

x∈X |∑

i∈I uie(xyi))|2, where X is a well-spacedset of real numbers, I is a finite set, {ui}i∈I are complex numbers and {yi}i∈I is asparse subsequence of the integers.

Basic examples of sparse sequences of integers are provided the sequence of val-ues of polynomials of degree ≥ 2 with integer coefficients. In a recent note,Liangyi Zhao (Monatschefte fur Mathematik, to appear in 2007) obtained, by anapplication of the double large sieve inequality of Bombieri and Iwaniec, a non-trivial inequality of the large sieve type when {yi}i∈I is the sequence of values ofpolynomials of degree 2 with integer coefficients. Zhao also shows that his esti-mate is essentially the best possible, except for the dependence of this estimateon the coefficients of the polynomial and the initial point of the interval I .

In a preprint authored together with D.S. Ramana titled The Large Sieve Inequalityfor Quadratic Polynomial Amplitudes, we combine Zhao’s method with an inter-polation argument due to Heath-Brown, to show that a modest improvement ofZhao’s inequality is still possible in respect of its dependence on the coefficientsof the polynomial and the initial point of I . In a work in preparation titled Baier’svariant of the Large Sieve Inequality for Quadratic Amplitudes we show that a variantof Zhao’s inequality due to S. Baier may also be refined.

Publications:

1. R. Balasubramanian and Gyan Prakash, Asymptotic formula for sum-free setsin abelian groups, Acta Arithmetica, Vol. 127, No. 2, 115-124, 2007.

Preprints:

1. R. Balasubramanian, Gyan Prakash and D.S. Ramana, Sum-free subsets offinite abelian groups of type III, in preparation.

2. Jean-Marc Deshouillers and Gyan Prakash, Large zero-free and incomplete sub-sets of Z/pZ, in preparation.

3. Gyan Prakash and D.S. Ramana, The Large Sieve Inequality for Quadratic Poly-nomial Amplitudes, http://arxiv.org/abs/0705.1739.

4. Gyan Prakash and D.S. Ramana, Baier’s Variant of the Large Sieve Inequalityfor Quadratic Polynomial Amplitudes, in preparation.


1. The First Indo-U.K. conference in Number Theory, India, September 2006.

35

2. International Conference on Number Theory, India, December 2006.

3. International Conference in Number Theory and Cryptography, India, February2007.

36


1. Institute of Mathematical Sciences, Chennai, India, September, 2006.

2. Institute of Mathematical Sciences, Chennai, India, March, 2007.


1. Large zero-free subsets of Z/pZ , First Indo-U.K. conference, Institute of Math-ematical Sciences, Chennai, September, 2006.

Other Activities:

1. I have been a referee for a paper submitted to the journal Proceedings- Math-ematical Sciences published by Indian Academy of Sciences.

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37

N. Raghavendra

Research Summary:Have been studying some questions on the cohomology of moduli spaces of bun-dles over a Riemann surface.

Publications:

1. Indranil Biswas and N. Raghavendra, The Atiyah-Weil criterion for holomor-phic connections, Accepted for publication in the Indian Journal for Pure andApplied Mathematics.

Other Activities:

1. Taught the first year graduate course Topology II, second semester, 2006–07.

2. Gave a course Introduction to Schemes to senior students.

3. Guided a second year graduate student, Amrutiya Sanjai Kumar Hansraj,in his project work on Riemann surfaces, during the first semester, 2006–07.

4. Was the convener of the Mathematics Graduate Studies Committee.

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38

B. Ramakrishnan

Research Summary:

1. Rankin-Cohen Brackets and Jacobi forms of several variables (with B.Sahu):

The Rankin-Cohen bracket is a differential operator, which sends modularforms to modular forms. Following Rankin’s method, D. Zagier computedthe n-th Rankin-Cohen bracket of a modular form g of weight k1 with theEisenstein series of weight k2 and then computed the inner product of thisRankin-Cohen brackets with a cusp form f of weight k = k1 + k2 + 2nand showed that this inner product gives the special value of the Rankinconvolution of f and g upto a constant. Following the work of Zagier, Y.Choie and W. Kohnen generalized the above result to Jacobi forms.Theycomputed the Petersson scalar product 〈F, [G,Ek,m]ν〉 of a Jacobi cusp formF against the Rankin-Cohen bracket [G,Ek,m]ν of a Jacobi form G and anEisenstein series Ek,m explicitly under a certain assumption on the weightof G and k. Though the concept of Rankin-Selberg convolution has notbeen done yet in the case of Jacobi forms, the above mentioned work ofChoie and Kohnen gives the special value of a kind of Rankin-Selberg typeconvolution of the Jacobi forms F and G. In this work, we study similarresults for Jacobi forms of higher degree, that is Jacobi forms on H× C(g,1).

2. A characterization of the space of new forms of half-integral weight anda conjecture of Zagier (with S. Gun and M. Manickam).

In our earlier work we showed the existence of a subspace of Mk+1/2(4)which is mapped to M2k(1) under the first Shimura map. By characteriz-ing the space of new forms in Sk+1/2(4N) with respect to the prime p = 2,we show that the space M (±,2)

k+1/2(4N), which is the subspace of Mk+1/2(4N)

consisting of forms which are eigenfunctions under the W (4) operator witheigenvalue ±1, is mapped to M2k(N) under a class of Shimura maps whenN is odd and square-free. This generalizes our earlier work. The presentwork gives new formulas for r2k+1(|t|n2), where t ≡ 1 (mod 4) is a square-free integer with (−1)kt > 0.

3. Twisted Averages ofL-functions (with M. Manickam and V. Kumar Murty).

W. Luo and D. Ramakrishnan used twisted averages of L-functions to char-acterize modular forms. More precisely, let f be a new form of integralweight k, level N with trivial character. They proved that for any real

39

σ ∈(k−1

2, k+1

2

),

limj→∞

1

pj−1

∑

χ mod pj

ord(χ) = pa

χ(m) L(f, χ, σ) =1

p

(1− 1

p

)af (m)

mσ.

They also proved a result for averages of quadratic twists. In this case, onthe right hand side, one gets not af(m) itself, but rather a rational functionin af (m) from which the Fourier coefficient can be recovered. It should benoted that they proved that the coefficients of the L-function (and hencethe L-function itself) is completely determined by certain special values oftwists of the L-function. In the present work, we derive similar implica-tions for the L-functions associated to new forms in the case of both integerand half-integer weight, by proving appropriate results with explicit errorterms. This work is in progress.

Publications:

1. (with B. Sahu) On the Fourier Expansions of Jacobi Forms of Half-Integral Weight,Int. J. Math. Math. Sci. Vol 2006.

Preprints:

1. (with B. Sahu) Differential operators on Jacobi forms of several variable

2. (with S. Gun, M. Manickam) A Characterization of the space of new forms ofhalf-integral weight and a conjecture of Zagier.

3. (with M. Manickam and V. Kumar Murty) Twisted averages of L-functions.


1. Attended the International Congress of Mathematicians (ICM) 2006 held atSpain during August 2006.

2. Attended and gave an invited talk in the International Conference on Num-ber Theory and Applications, RKM Vivekananda College, Chennai duringDecember 27–29, 2006.

40

3. Attended and gave a talk in the International Conference on Number The-ory and Cryptography, held at HRI, Allahabad during Feb 2007.

4. Attended and gave an invited talk in the 21st Automorphic Forms Work-shop held at the University of California at Santa Barbara, Santa Barbaraduring March 2007.


1. IHES, Paris, France. April 2006.

2. University of Toronto at Mississauga, Mississauga, Canana. June-July, 2006.


1. On a conjecture of Zagier, Aachen-Koln-Lille-Siegen seminar on Automor-phic Forms, RWTH, Aachen, April 2006.

2. An estimate for a certain average of the special values of character twists of modularL-functions, Number Theory Seminar, Queen’s University, Kingston, July2006.

3. On a conjecture of Zagier, Symposium in Mathematics (in the memory of Pro-fessor I.S. Luthar), Panjab University, s Chandigarh, March 2007.

Other Activities:

1. Guiding one student for his Ph.D and another student is doing a secondyear project under me.

2. Member of Faculty Recruitment Committee (Mathematics).

3. One of the organizers of the International Conference on Number Theoryheld at HRI during December 2006.

4. Dean of Administration (since October 2005).

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41

D. Surya Ramana

Research Summary:

In a preprint titled Arithmetical applications of an identity for the Vandermonde deter-minant we address a general question particular cases of which are the problemof determining upper bounds for the number of integer points on small arcs ofconics considered in a number of works of J. Cilleruelo et. al. ( Proc. A.M.S.,Vol. 115, 1992, Duke Math. Journal, Vol. 76, 1994, Journal of Number Theory,Vol. 63, 1997, Acta Arith., Vol. 85, 1998) and problem of showing that the numberof divisors of an integer N lying in certain arithmetical progressions is boundedindependently of N , considered in H. Lenstra (Math. of Comp., Vol. 42, 1984).These problems are of interest not only for their intrinsic appeal but also for theirrelation to a number of other questions on the interface between harmonic anal-ysis and number theory, as described recently by J. Cilleruelo and A. Granville(Math. Arxiv, NT/0608109, August, 2006).

In the preprint cited, we present an identity for the Vandermonde determinantthat provides rather simple proofs for a number of results given in the works of J.Cilleruelo et. al. as well as the result of Lenstra mentioned above. We also observethat this identity may be used to deduce a special case of the overlapping theoremof J. Cilleruelo and G. Tenenbaum (preprint, 2005), by which means, or by closelyrelated methods, the aforementioned results are obtained in the literature.

A particular case of the results on integer points on arcs of conics dealt with inthe preprint described above shows that there is a constant c(d) such any arc ofthe conic X2 + dY 2 = R of length c(d)|R|1/6 contains no more than two integerpoints, where d and R are integers. In a work in preparation titled Arcs of ConicsContaining Three Integer Points we provide a family of examples of arcs of lengthsc′(d)R1/6 containing exactly three integer points for some c′(d) > c(d). In partic-ular, when d is not congruent 2 modulo 4 we show that such arcs exist for anyc > c(d) and that the triples of integer points lying on such arcs may all be foundin single orbit under the action of the group Γ(4d) on triples of integer points inthe plane. These results generalise the result of J. Cilleruello (Acta Arith., Vol. 51,1991) where the case of the circle is studied.

A subset of an abelian group is said to be sum-free if the sum of any pair ofelements of this subset lies in the complement of this subset. In the study ofsum-free subsets of finite abelain groups, it turns out to be convenient to classifythe groups according to the residue classes of the primes dividing their ordersmodulo 3. A finite abelian group is called type III when all the divisors of theorder of G are congruent to 1 modulo 3. In earlier work with Gyan Prakash, we

42

obtained, with the aid of a classification theorem for largest sum-free subsets oftype III due to R. Balasubramanian and Gyan Prakash, a formula for the numberof orbits of L, the set of all largest sum-free subsets of G, when G is of type III.

In a joint work in preparation with R. Balasubramanian and Gyan Prakash titledSum-free Subsets of Finite Abelian groups of Type III we describe the work mentionedabove and give a further application of the classification theorem. More precisely,for a finite abelian groupH let S(k, l, H) denote the set {B ⊂ H : |B| = k, |B+B| =l}, where B + B is the set of sums {x + y|(x, y) ∈ B × B}. The aforementionedclassification theorem enables us to obtain a relation between the cardinality ofthe set SF (G), where SF (G) is the set of all sum-free subsets of G, and that ofS(k, l, H), where H is a supplement of a copy of Z/mZ in G with m being theexponent of G. These results are obtained by refining the methods developedby Ben Green and Imre Ruzsa (Israel J. Math., Vol. 147, 2005) for the study ofsum-free subsets in finite abelian groups.

When G is the additive group of a finite dimensional vector space over a finitefield, we improve the estimate for S(k, l, G) provided by Ben Green (Combinator-ica, Vol. 25, 2005). This, together with the results mentioned above, then allowsus to obtain a substantial improvement for the upper bound of the cardinality ofSF (G), when G = (Z/pZ)r with p being a prime congruent to 1 modulo 3. Thework in preparation mentioned above ends with an account of this improvement.

An important requirement in the context of inequalities of the large sieve type isto obtain estimates for the sum

∑x∈X |

∑i∈I uie(xyi))|2, where X is a well-spaced

set of real numbers, I is a finite set, {ui}i∈I are complex numbers and {yi}i∈I is asparse subsequence of the integers.

Basic examples of sparse sequences of integers are provided the sequence of val-ues of polynomials of degree ≥ 2 with integer coefficients. In a recent note,Liangyi Zhao (Monatschefte fur Mathematik, to appear in 2007) obtained, by anapplication of the double large sieve inequality of Bombieri and Iwaniec, a non-trivial inequality of the large sieve type when {yi}i∈I is the sequence of values ofpolynomials of degree 2 with integer coefficients. Zhao also shows that his esti-mate is essentially the best possible, except for the dependence of this estimateon the coefficients of the polynomial and the initial point of the interval I .

In a preprint authored together with Gyan Prakash titled The Large Sieve Inequalityfor Quadratic Polynomial Amplitudes, we combine Zhao’s method with an interpo-lation argument due to Heath-Brown, to show that a modest improvement ofZhao’s inequality is still possible in respect of its dependence on the coefficientsof the polynomial and the initial point of I . In a work in preparation titled Baier’svariant of the Large Sieve Inequality for Quadratic Amplitudes we show that a variantof Zhao’s inequality due to S. Baier may also be refined.

43

Preprints:1. D.S. Ramana,Arithmetical applications of an identity for the Vandermonde deter-

minant, http://arxiv.org/abs/0705.1739.

2. D.S. Ramana, Arcs of Conics Containing Three Integer Points,in preparation .

3. R. Balasubramanian, Gyan Prakash and D.S. Ramana, Sum-free subsets offinite abelian groups of type III, in preparation .

4. Gyan Prakash and D.S. Ramana, The Large Sieve Inequality for Quadratic Poly-nomial Amplitudes, http://arxiv.org/abs/0705.1739 .

5. Gyan Prakash and D.S. Ramana, Baier’s Variant of the Large Sieve Inequalityfor Quadratic Polynomial Amplitudes, in preparation .

Conference/Workshops Attended:1. The First Indo-U.K. conference in Number Theory, India, September 2006.

2. Conference in Number Theory, India, October 2006.

3. International Conference on Number Theory, India, December 2006.

4. International Conference in Number Theory and Cryptography, India, February2007.

Visits to other Institutes:1. Indian Institute of Technology, Mumbai, India, January, 2007.

Invited Lectures/Seminars:1. Orbits of Largest Sum-free Subsets in Abelian Groups of Type III, First Indo-U.K.

conference, Institute of Mathematical Sciences , Chennai, September, 2006.

2. Large Sieve Inequality for Quadratic Polynomials, Conference on Number The-ory, Panjab University, Chandigarh, October, 2006.

Other Activities:1. Assisted the Director, H.R.I. in the selection process for the institute’s engi-

neering consultant.

2. Conducted the mathematics part of the Annual Science Talent Test of H.R.I..

3. Served on the Local Works Committee of H.R.I. for the year 2006 to 2007.

· · ·44

Ritumoni Sarma

Research Summary:

I have showed the virtual 3 generation property (known for arithmetic groups)for S-arithmetic groups under certain rank conditions. We are expecting to re-duce the rank condition to improve the very result.

If the lengths of the two sides and the angle between them are known then weknow the length of the third side. This is often referred to as the cosine formula.This can be generalized to the non-Euclidean spaces. The formula is known forthe classical rank one symmetric spaces. There is an exceptional rank one sym-metric space. We write the so called cosine formula for this space and expectingsome interesting application.

Publications:

1. Ritumoni Sarma, On Virtual 3-Generation of S-Arithmetic Subgroups of SL2,Asian Journal of Mathematics Vol. 10, No. 4, pp. 749-756.

Preprints:

1. Ritumoni Sarma, Virtual 3-generation for S-arithmetic groups (in preparation).

2. Ratnakumar P.K. and Ritumoni Sarma, A cosine formula for the rank one sym-metric spaces (in preparation).


1. Asymptotic Group Theory (Midrasha Mathematicae), Israel, May, 2006.

2. International Congress of Mathematicians, Spain, August, 2006.

3. Geometric and Asymptotic Group theory with Applications, Spain, Septem-ber, 2006.

Other Activities:

1. Gave a course on elementary Topology as a part of VSSP in HRI, Allahabad,July (first half) 2006.

2. Participated as a tutor in AFS for college teachers, IITB, Mumbai, July (sec-ond half) 2006.

· · ·45

R. Thangadurai

Research Summary:

(1) Relative Davenport’s Constant. (Reference. [1] R. Thangadurai, The variant ofDavenport’s constant, Proc. Indian Acad. Sci. (Math. Sci.), 117, 1-11, (2007)).Let G be a finite abelian group of exponent n. Let A be a non-empty subset of{1, 2, · · · , n}. By dA(G), we denote the least positive integer t such that for anysequence g1, g2, · · · , gt (not necessarily distinct) in G, we can find a subsequencegi1, gi2, · · · , gi` satisfying

∑

j=1

ajgij = 0 in G.

When A = {1}, then dA(G) = D(G), the well-known Davenport’s constant.Hence dA(G) generalizes the classical Davenport’s constant. In [1], we have provedthe following result.

Theorem 1. Let G ∼ Zpe1 ⊕ Zpe2 ⊕ · · · ⊕ Zpel where 1 ≤ e1 ≤ e2 ≤ · · · ≤ el areintegers. Then, for any non-empty subset A of {1, 2, · · · , pel} such that the elements ofA are incongruent modulo p and non-zero modulo p, we have,

dA(G) ≤⌈

1

|A|

(1 +

l∑

i=1

(pei − 1)

)⌉

where dxe denotes the smallest positive integer greater than or equal to x.

Corollary 1.1. Let G ∼ Zdp where d ≥ 1 integer. Then for any non-empty subset A of{1, 2, · · · , p− 1}, we have,

dA(G) ≤⌈

1

|A|(d(p− 1) + 1)

⌉.

For any integer x ≥ 1, we denote ]x[ by {1, 2, · · · , x}.Corollary 1.2. Let G ∼ Zdp where d ≥ 1 integer. If(a) A =]p− 1[, then dA(G) = d+ 1;(b) A1 = {a ∈]p− 1[: a ≡ x2 (mod p) for some x ∈]p[}, then dA1(G) = 2d+ 1;(c) A2 = {a ∈]p− 1[: a 6≡ x2 (mod p) for all x ∈]p[}, then dA2(G) = 2d+ 1;(d) A3 = {a ∈]p− 1[: a generates F∗p}, then dA3(G) = 2d+ 1;(e)A4 = {a ∈]p−1[: a ∈ A2\A3}, then dA4(G) = 2d+1 holds for all primes p 6= 22m +1

for some m ∈ N.

46

(f) A5 ⊂]p − 1[ such that |A5| = (p − 1)/2 and if x ∈ A5, then p − x 6∈ A5, thendA5(Z

dp) = 2d+ 1.

(g) A =]r[⊂]p[ and r ≥ d, then

dA(G) =

⌈d(p− 1) + 1

r

⌉.

Other than this study, along with Gao, Hou and W. Schmid, we proved someresults in the classical zero-sum lattice point constant for the group G ∼ Z3

n whenn = 3, 5, 2a3b. Also, we proved some inverse problem related to this lattice pointproblem too.

(2) Distribution of quadratic non-residues which are not primitive roots mod-ulo p. (Reference. [2] S. Gun, F. Luca, P. Rath, B. Sahu and R. Thangadurai, Distri-bution of residues modulo p, Preprint, 2006.)In [2], we studied the distribution of quadratic non-residues which are not prim-itive roots modulo p. More precisely, we studied that whether for large enoughprimes p has arbitrarily long string of consecutive quadratic non-residues whichare not primitive roots modulo p? We abbreviate quadratic non-residues whichare not primitive roots modulo p by QNRNP. Indeed, we proved, in [2], the fol-lowing results.

Theorem 2. Let ε ∈ (0, 1/2) be fixed and let N be any positive integer. Then for allprimes p ≥ exp((2ε−1)8N ) satisfying

φ(p− 1)

p− 1≤ 1

2− ε,

we can find N consecutive QNRNP’s modulo p.

Corollary 2.1. For any given ε ∈ (0, 1/2) and natural number N , for all primes p ≥exp((2ε−1)8N ) and satisfying φ(p − 1)/(p − 1) ≤ 1/2 − ε, the sequence g1 + N, g2 +N, . . . , gk +N contains at least one QNRNP.

Theorem 3. There exists an absolute constant c0 > 0 such that for almost all primes

p, there exist a string of Np =

⌊c0

log p

log log p

⌋of quadratic non-residues which are not

primitive roots.

Theorem 4. For every positive integer N there are infinitely many primes p for which1, 2, . . . , N are quadratic residues modulo p, and there exist both a string of N consec-utive QNRNP ’s as well as a string of N consecutive primitive roots. The smallest suchprime can be chosen to be < exp(exp(c1N

2)), where c1 > 0 is an absolute constant.

Apart from these results, we continue our study of this distribution problems ofthese residues. For instance, we are tackling the following two problems. (i) For a

47

given integer a which is not a square, can one find infinitely many primes p suchthat a is a QNRNP modulo p?(ii) Whether the spacing distribution of these residues modulo p behaves likePoissonian with mean spacing tending to infinity?

(3) Collected works of Dr. S. S. Pillai. Most of the papers of Dr. S. S. Pillai hasbeen typed during this period. Also, we have collected many old letters of Dr.S. S. Pillai from Dr. S. Chowla, T. Vijayaraghavan etc. This work is expected tocomplete by the end of 2007.

Publications:

1. W. D. Gao and R. Thangadurai, On zero-sum Sequences of prescribed length,Aequationes Math., 72, 201-212, (2006)

2. R. Thangadurai, A variant of Davenport’s Constant, Proc. Indian. Acad. Sci.(Math. Sci.), 117, 1-11, (2007)

3. W. D. Gao, Q. H. Hou, W. A. Schmid and R. Thangadurai, On short zero-sumsubsequences - II, Integers, 7 A-21, 22pp, (2007)

Preprints:

1. S. Gun, F. Luca, P. Rath, B. Sahu and R. Thangadurai, Distribution of residuesmodulo p, Submitted for Publication.

2. R. Thangadurai, Distribution of quadratic non-residues which are not primitiveroots modulo p - II, in preparation.

3. P. Moree and R. Thangadurai, Distribution of quadratic non-residues which arenot primitive roots modulo p - III, in preparation.


1. Number Theory and Harmonic Analysis, University of Lille, France, June, 2006

2. Additive Number Theory, University of Saint-Etienne, France, June, 2006


1. Center for Combinatorics, Nankai University, Tianjin, P. R. China, April,2006.

2. University of Lille, Lille, France, June, 2006.

48

3. University of Saint-Etienne, Saint-Etienne, France, June, 2006.


1. Davenport’s Constant, Combinatorics Seminar, Center for Combinatorics, NankaiUniversity, Tianjin, P.R. China, April, 2006.

2. Davenport’s Constant, Number Theory Seminar, University of Lille, Lille,France, June, 2006.

Other Activities:

1. Seminar Course for the first year graduate students, August-December, 2006.

2. Galois Theory for the first year graduate students, January-May, 2006.

3. Office Furniture Committee, Convener, 2006-07.

4. Library Committee, Member, 2006-07.

· · ·

49

Manoj Kumar Yadav

Research Summary:

1. Let G be a finite p-group and N be a non-trivial proper normal subgroup of G.(G,N) is called a Camina pair if xN ⊆ xG for all x ∈ G − N , where xG denotesthe conjugacy class of x in G. It follows that (G,N) is a Camina pair if and only ifN ⊆ [x,G] for all x ∈ G−N , where [x,G] = {[x, g]|g ∈ G}. Let Aut(G) denote thegroup of all automorphisms of G. In this research note we prove the followingtheorem:

Theorem. Let G be a finite p-group such that (G,Z(G)) is a Camina pair. Then|G| divides |Aut(G)|.This theorem extends the known classes of finite p-groups for which the followingwell known conjecture holds:

Conjecture. Let G be a non-cyclic p-group of order pn, where n ≥ 3. Then |G|divides |Aut(G)|.2. We give a sufficient condition on a finite p-group G of nilpotency class 2 sothat Autc(G) = Inn(G), where Autc(G) and Inn(G) denote the group of all classpreserving automorphisms and inner automorphisms of G respectively. Next weprove that if G and H are two isoclinic finite groups (in the sense of P. Hall), thenAutc(G) ∼= Autc(H). Finally we study class preserving automorphisms of groupsof order p5, p an odd prime and prove that Autc(G) = Inn(G) for all the groupsG of order p5 except two isoclinism families.

Publications:

1. E. C. Dade and Manoj K. Yadav, Finite groups with many product conjugacyclasses, Israel J. Math. 154, 29-49, (2006)

Preprints:

1. Manoj K. Yadav, On automorphisms of finite p-groups, J. Group Theory, toappear

2. Manoj K. Yadav, On automorphisms of some finite p-groups, Proc. Indian Acad.Sci., Math. Sci., to appear


1. Victor Rothschild Memorial Symposia 10th Jerusalem Midrasha Mathematicae, Is-rael, May, 2006.

50

2. Classification of Reductive Algebraic Groups, India, December, 2006.

3. International Conference on Number Theory and Cryptography, India, Feb., 2007.


1. Indian Statistical Institute, Bangalore, India, Dec. 06, 2006 to Jan. 05, 2007.

Other Activities:

1. Gave seven lectures in VSSP at HRI on Group Theory, June, 2006.

· · ·

51

Veerendra Vikram Awasthi

Research Summary:

During the academic year 2006-2007, I have been working mainly on these topicswith Professor Satya Deo, my Ph. D. Supervisor:

1. Inverse system of nonempty objects with empty limit.

We have constructed a concrete example of an inverse system of nonemptyobjects with empty limit. It has been often quoted, without giving an exam-ple, that there are inverse limit systems in which all the objects are nonemptyand the connecting maps are onto, but the inverse limit is empty. By our ex-ample, it will easily follow that we can have such an inverse system in thecategory of modules and homomorphisms, category of topological spacesand continuous maps, etc.

2. Cohomological Dimension Theory with respect to different cohomologies.

we have been trying to compute all the singular homology groups of then-dimensional Hawaiian earring. Barrat and Milnor had showed only thatthese groups are nonzero in infinitely many dimensions, but the actual com-putation had been an open problem for quite some time. We have suc-ceeded in determining them precisely in several dimensions.

In the theory of cohomological (or homological) dimensions, it is invariablythe Cech cohomology or the sheaf theoretic cohomology which is used. Thesimple reason for such a preference is the fact that if X is a paracompactHausdorff space of covering dimension n, then the Cech homology groupssatisfy the property thatHq(X;G) = 0, ∀q > n and for all coefficientsG. Thequestion as to what happens if one uses some other cohomology or homol-ogy theory, was first answered very decisively by Barratt and Milnor. Theyconstructed a compact, connected, metric space X of covering dimensionr (for any given r ≥ 2) which had the surprising property that its singularhomology groups Hq(X;Q) with rational coefficients were non-zero for in-finitely many values of q greater than r. More precisely, they proved thatHq(X;Q) 6= 0 whenever q ≡ 1mod(r− 1). Consequently, the integral singu-lar homology groups Hq(X) 6= 0 for q ≡ 1mod(r− 1). We have proved theirresult that Hq(X) = 0 for r < q < 2r − 1. We have also constructed a com-pact, connected, metric space Y of covering dimension 2r− 2 (r > 2) whichhas the property that Y is (r− 1)-connected and Hq(X;Q) 6= 0, ∀q ≥ 2r− 2.

52

Preprints:

1. Veerendra Vikram Awasthi and Satya Deo, An Inverse system of nonemptyobjects with empty limit, (communicated).

2. Veerendra Vikram Awasthi and Satya Deo, Homology and Dimension - Furtherpathological examples, (under submission).


1. Symposium on “Analysis and Approximation”, Department of Mathematics, R.D. University, Jabalpur, INDIA, April, 2006.

2. International Workshop and conference on “Geometric Methods in Topology”, In-dian Institute of Sciences (IISc.) Banglore, INDIA, June, 2006.

3. 72nd Annual Conference of the Indian Mathematical Society, Department of Math-ematics, R. D. University, Jabalpur, INDIA, December, 2006.


• Strongly Contractible Polyhedra which are not Simply Contractible at n Points forany n ≥ 2, 72nd Annual Conference of the Indian Mathematical Society, R.D. University, Jabalpur, INDIA, December, 2006.

· · ·

53

Soumya Das

Research Summary:

Submitted my Msc. dissertation titled, “The Brauer-Hasse -Noether theorem forNumber fields”, under the supervision of Dr. Chandan Singh Dalawat. Somesimplifications of proofs from Jurgen Neukirch’s book titled, “Cohomology ofNumber fields” were done. The main result was the computation of the Brauergroup of a Number field. Currently I am working on the problem of determiningthe Brauer-Wall group of a number field, based on the above mentioned result.


1. ISI Workshop on Group theory, India, January, 2007.

2. International Conference on Number theory and Cryptography, India, February2007.


1. Indian Statistical institute, Bangalore, India, December-January 2007.

Other Activities:

1. Graded Brauer groups, Graduate Seminar, Harish Chandra Research insti-tute, Allahabad, January 2007.

· · ·

54

Tanusree Pal

Research Summary:

We classified the isomorphism classes of the integrable irreducible modules withfinite dimensional weight spaces for the multi-loop Lie algebras and a class of thetwisted multi-loop Lie algebras in the paper “Irreducible Integrable Representa-tions of Graded Multi-loop Lie Algebras.” Further study on the representationsof the integrable modules of the multi-loop Lie algebras are being continued.

Preprints:

1. Tanusree Pal and Punita Batra, Irreducible Integrable Representations of GradedMulti-loop Lie Algebras. , arXiv:0706.0448v1 [math.RT]


1. ISI Workshop on Group Theory, India, December 2006.


1. Institute of Mathematical Sciences, Chennai, India, July-August 2006.

· · ·

55

Anupama Panigrahi

Research Summary:

I am continuing research on Zero-sum problems and related areas. Also trying tostudy some deeper aspects of Additive Number Theory. Discussions with Prof. R.Balasubramanian and other researchers at ICTP was very helpful and inspiring.I Already have some new results and hoping to solve some open problems soon.


1. International Conference on “ Number Theory”, HRI, India, December, 2006.

2. International Conference on“Number Theory and Cryptography”, HRI, India,February, 2007.

· · ·

56

Supriya Pisolkar

Research Summary:

Chow groups of zero cycles of Chatelet surfaces over local fieldsLet K be a finite extension ofQp, p-prime. By a Chatelet surfaceX over K we meana smooth projective surface K-birational to a surface given by the equation:

y2 − dz2 = f(x)

where f(x) is a monic cubic polynomial in x with coefficients in K. I am workingon the computation of the Chow group A0(X)0 of 0-cycles of degree zero modulorational equivalence of such surfaces. The case of Chatelet surfaces where f(x)splits into three linear factors has been considered by Prof. Dalawat [arxiv:math/060433].I have considered Chatelet surfaces for which f(x) is either of the form x(x2 − e)or is an irreducible cubic. The complete result for the irreducible case has nowbeen obtained. When f(x) = x(x2 − e), the calculation has been done when p isodd and when K = Q2. The work for finite extensions of Q2 is in progress.


1. Asian French summer school in Algebraic geometry and Number Theory, Bu-res,Paris - July 06.

2. Workshop and conference in Number Theory by Ramanujan Mathematical Society,Hyderabad - June 06

3. Number Theory conference, HRI, Allahabad - Jan 07

· · ·

57

Brundaban Sahu

Research Summary:

1. The derivative of a modular form is not a modular form. But there aremany interesting connections between differential operators and the the-ory of modular forms. In 1956, R. A. Rankin gave a general description ofthe differential operators which send modular forms to modular forms. In1977, H. Cohen constructed modular forms from derivatives of two mod-ular forms. In 1990, Zagier studied the algebraic properties of these bilin-ear operators and called them Rankin-Cohen brackets. Following Rankin’smethod, Zagier computed the n-th Rankin-Cohen bracket of a modularform g of weight k1 with the Eisenstein series of weight k2 and then com-puted the inner product of this Rankin-Cohen brackets with a cusp form fof weight k = k1 + k2 + 2n and showed that this inner product gives thespecial value of the Rankin-Selberg convolution of f and g upto a constant.

The theory of the classical Jacobi forms onH×C has been extensively stud-ied by Eichler and Zagier. The study of Rankin-Cohen bracket for Jacobiforms using the heat operator started with the works of YoungJu Choie.Following the work of Zagier, Y.J Choie and Kohnen generalized the aboveresult of Zagier to Jacobi forms.They computed the Petersson scalar prod-uct 〈F, [G,Ek,m]ν〉 of a Jacobi cusp form F against the Rankin-Cohen bracket[G,Ek,m]ν of a Jacobi form G and an Eisenstein series Ek,m explicitly un-der a certain assumption on the weight of G and k. Though the conceptof Rankin-Selberg convolution has not been done yet in the case of Jacobiforms, the above mentioned work of Choie and Kohnen gives the specialvalue of a kind of Rankin-Selberg type convolution of the Jacobi forms Fand G.

We study the similar results for Jacobi forms of higher degree, that is Ja-cobi forms on H × C(g,1) (Preprint [1]). It is also possible to extend thismethod/result to Hermitian Jacobi forms, that is Jacobi forms arising fromnumber fields (of degree two). The work is in progress for the case Hermi-tian Jacobi form.

2. The congruences between modular forms is another interesting topics inmodular forms. First it was studied by J. Sturm in 1987. The question isto find the least positive integer n such that their n−th Fourier coefficientsmust differ if the two modular forms are not identical. Recently there are

58

improvements by Ram Murty and Kohnen. Using some relationship of Ja-cobi forms and modular forms, we study the congruences between Jacobiforms. The work is in progress.

3. We study the distribution of quadratic non-residues which are not primitiveroots (QNRNP) (Preprint [2]). We prove the following theorems.

Theorem 1. Let ε ∈ (0, 1/2) be fixed and let N be any positive integer. Then for allprimes p ≥ exp((2ε−1)8N ) satisfying

φ(p− 1)

p− 1≤ 1

2− ε,

we can find N consecutive QNRNP’s modulo p.

The above theorem generalizes a result of A. Brauer and a result of our pre-vious paper “Distribution of Quadratic non-residues which are not prim-itive roots, Math. Bohem. 130 (2005), no. 4, 387–396 (with S. Gun, R.Thangadurai and B. Ramakrishnan).

Given a prime number p, we let

k :=p− 1

2− φ(p− 1)

denote the number of QNRNP’s modulo p and we write g1 < g2 < . . . < gkfor the increasing sequence of QNRNP’s.

Corollary. For any given ε ∈ (0, 1/2) and natural number N , for all primes p ≥exp((2ε−1)8N ) and satisfying φ(p−1)/(p−1) ≤ 1/2−ε, the sequence g1 +N, g2 +N, . . . , gk +N contains at least one QNRNP.

Theorem 2. There exists an absolute constant c0 > 0 such that for almost all primes

p, there exist a string of Np =

⌊c0

log p

log log p

⌋of quadratic non-residues which are

not primitive roots.

Theorem 3. For every positive integer N there are infinitely many primes p forwhich 1, 2, . . . , N are quadratic residues modulo p, and there exist both a stringof N consecutive QNRNP ’s as well as a string of N consecutive primitive roots.The smallest such prime can be chosen to be < exp(exp(c1N

2)), where c1 > 0 is anabsolute constant.

59

Publications:1. B.Sahu and B. Ramakrishnan, On the Fourier Expansions of Jacobi Forms of

Half-Integral Weight, Int. J. Math. Math. Sci. Vol 2006.

Preprints:1. B. Sahu, B. Ramakrishnan, Differential operators on Jacobi form of several vari-

able

2. B. Sahu, S. Gun, Florian Luca, P. Rath and R. Thangadurai, Distribution ofResidues Modulo p.

Conferences/Workshops Attended:1. International Conference on Number Theory and Cryptography (Feb 23-27, 2007),

HRI, Allahabad

2. International Conference on Number Theory and Applications (Dec 27-29, 2006),RKM Vivekananda College, Chennai

3. International Conference on Number Theory (Dec 1-5, 2006), HRI, Allahabad

4. India-UK Number Theory Conference (Sept 18-23, 2006), IMSc, Chennai

Invited Lectures/Seminars:1. On the Rankin-Cohen Brackets for Jacobi Forms of higher degree, International

Conference on Number Theory and Applications (Dec 27-29, 2006) in RKMVivekananda College, Chennai.

2. On the Fourier expansion of Jacobi Forms of half-integral weights, InternationalConference on Number Theory (Dec 1-5, 2006) in HRI, Allahabad.

3. Basic Algebra, Interactive Mathematics Training Camp, Regional Institute ofEducation, June 2006, Bhubaneswar (sponsored by NBHM), organized byInstitute of Mathematics and Applications, Bhubaneswar.

4. Lectures on Elementary Number Theory, Interactive Mathematics Training Camp, Regional Institute of Education, June 2006, Bhubaneswar (sponsored byNBHM), organized by Institute of Mathematics and Applications, Bhubaneswar.

Academic recognition/Awards:1. I became a Reviewer of Mathematical Reviews, American Mathematical So-

ciety from March 2007.

· · ·60

Mahender Singh

Research Summary:

During 2006 - 2007, I have been working mainly on Compact TransformationGroups. Particularly, I have been investigating relations between the structure ofthe cohomology ring of a space and that of its fixed point set under a compactgroup action using techniques of spectral sequences.

Conferences/Workshops attended:

1. International Conference on Geometric Methods in Topology, Indian Institute ofScience, India, June, 2006.

2. International Conference in Number Theory, HRI, India, December, 2006.

Other Activities:

Taught a mini course on Quotient Spaces in Visiting Student’s Programme-2006.· · ·

61

ACADEMIC REPORT - PHYSICS

Jasjeet Singh Bagla

Research Summary:The distribution of galaxies can be described in a statistical manner using a hier-archy of correlation functions. This full hierarchy is often difficult to compute andrepresent and reduced moments of the distribution are often used to describe itskey features. The initial density perturbations are Gaussian and all the momentscan be expressed in terms of the second moment. The late time distribution ofgalaxies is highly non-Gaussian and the values of reduced moments are verysensitive to the form of the high density non-Gaussian tail. We studied the non-Gaussian tail of the probability distribution function of density in cosmologicalN-Body simulations for a variety of initial conditions. Further, we studied the dif-ferences between the distribution in real space and redshift space. The form of thedistribution function in redshift space is of great significance as galaxy surveysprobe this and not the real space analogue predicted using theoretical models.We have shown that redshift space distortions in the non-linear regime dominateover signatures of initial conditions or the cosmological background. We find thatat scales smaller than the scale of non-linearity the differences in Skewness, etc.for different models are very small compared to the corresponding differences inreal space. We show that bias also leads to smaller values of higher moments,but the redshift space distortions are typically the dominant effect. In particular,we are able to explain the observations of reduced moments from galaxy surveysand also the differences between these and the predictions for reduced momentsin real space. This work was done with Suryadeep Ray.

Publications:

1. Bagla J. S. and Prasad Jayanti, Effects of the size of cosmological N-Body simula-tions on physical quantities — I: Mass Function, MNRAS 370, 993 (2006)

Preprints:

1. Bagla J. S. and Ray Suryadeep, Gravitational Clustering in Redshift Space: Non-Gaussian Tail of the Cosmological Density Distribution Function, astro-ph/0604598.

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1. Emerging Trends in Physics 2006, SGTB Khalsa College, Delhi, India, Septem-ber, 2006.

2. IUCAA Reference Centre Workshop on Advanced Topics in Data Analysis in Cos-mology and Gravitational Wave Astronomy, University of Delhi, Delhi, India,October, 2006.

3. Study of Hot Diffuse Gas with ASTROSAT, Bangalore, India, December, 2006.

4. 24th meeting of the Indian Association for General Relativity and Gravitation (IA-GRG), Jamia-Millia Islamia University, Delhi, India, February, 2007.

5. 25th meeting of the Astronomical Society of India, Osmania University, Hyder-abad, India, February, 2007.

6. IUCAA-MPA workshop, Pune, India, March, 2007.


1. IUCAA, Pune, India, July, 2006.

2. TIFR, Mumbai, India, September, 2006.

3. Raman Research Institute, Bangalore, India, February, 2007.

4. IUCAA, Pune, India, March, 2007.


1. Simulating the Universe, Emerging Trends in Physics 2006, SGTB Khalsa Col-lege, Delhi, September 2006.

2. Large Scale Structures in the Universe, IUCAA Reference Centre Workshopon Advanced Topics in Data Analysis in Cosmology and Gravitational WaveAstronomy, University of Delhi, Delhi, October 2006.

3. From Tides to Colliding Galaxies, Quanta 2006, CMS Lucknow, November2006.

4. Cosmology with X-Ray observations, Study of Hot Diffuse Gas with ASTROSAT,Bangalore, India, December 2006.

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5. Large Scale Structure and Redshift Surveys, 24th meeting of the Indian Asso-ciation for General Relativity and Gravitation (IAGRG), Jamia-Millia IslamiaUniversity, Delhi, India, February 2007.

6. Recent Results on Galaxy Clustering from the SDSS and other surveys, 25thmeeting of the Astronomical Society of India, Osmania University, Hyder-abad, India, February 2007.

7. Does Size Matter: Effects of finite box size in cosmological N-Body simulations, As-trophysics Seminar, Raman Research Institute, Bangalore, February 2007.

8. Possibilities for collaboration in computational cosmology, IUCAA-MPA work-shop, Pune, India, March 2007.

Other Activities:

• Two students did summer project with me in May-July, 2006.

• Two students did industrial training with me in May-July, 2006 during whichthey worked on some aspects of cluster computing.

• I co-organised a school for high school students from the Allahabad andneighbouring areas. Hindi was the medium of instruction in this school.This school was held during May 22-26, 2006. I also gave two lectures inthis school.

• A new Linux cluster for high performance scientific computing was addedto the cluster facilities. This cluster has 35 dual processor computers anda high performance interconnect. The theoretical peak performance of thiscluster is 1.6 TeraFlops and it is expected that scientific applications canperform at up to 1.1 TeraFlops. I designed the configuration for this clusterand am taking care of installation and system administration. Several otherfacilities have also been added to the cluster facilities during the last year.

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64

Sandhya Choubey

Research Summary:

Sterile neutrinos have been the subject of much discussion recently, following themuch-awaited MiniBooNE results. One way to look for presence of sterile neu-trinos is to look at signature of sterile neutrinos in the supernova neutrino signalin next generation detectors. We have studied these signatures in the next gener-ation megaton water Cerenkov detectors and in the upcoming km3 neutrino tele-scopes like IceCube. Time dependent modulation of the neutrino signal emergingfrom the sharp changes in the oscillation probability due to shock effects is shownto be a smoking gun signal for the existence of sterile neutrinos. These modula-tions and even the entire expected neutrino event spectra is seen to be differentfor the case with only three active neutrinos and the cases where there are ad-ditional sterile species, mixed with the active neutrinos. Effect of turbulence istaken into account and its seen that the shock effects even though diluted, arenot completely washed out. Supernova neutrino signal in water detectors couldtherefore be used to give unambiguous proof for the existence of sterile neutri-nos. Finally, these time dependent modulations in the signal due to shock effectcan be used to trace the evolution of the shock wave inside the supernova.

Foremost among the next generation terrestrial neutrino experiments are the fu-ture betabeam and neutrino factory set-ups. A betabeam facility might come upat CERN and an intensive R&D is underway to look into its feasibility. At thesame time we are working hard in India to build the detector INO, which willhave 50 ktons of magnetized iron, interleaved with glass resistive plate cham-bers, which will act as the active detector element. We underscore the physicsadvantage of an experiment where neutrinos produced in a beta-beam facility atCERN are observed in a large magnetized iron calorimeter (ICAL) at the India-based Neutrino Observatory (INO). The CERN-INO distance is close to the so-called “magic” baseline which helps evade some of the parameter degeneraciesand allows for a better measurement of the neutrino mass hierarchy and θ13. Weexpound the possibility of using radioactive 8B and 8Li as the source isotopes forthe νe and νe beta-beam, respectively, and show that very good sensitivity to boththe mass hierarchy and θ13 is possible with a boost γ in the 250-500 ballpark.

Betabeams can also be very efficiently detected in water Cerenkov detectors, whereone would be able to detect the electron type neutrinos. We show that the earthmatter effects in the νe → νe survival probability can be used to cleanly determinethe third leptonic mixing angle θ13 and the sign of the atmospheric neutrino masssquared difference, ∆m2

31, using a β-beam as a νe source and a megaton waterCerenkov detector.

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Large matter effects in atmospheric neutrino experiments can also help us to de-termine the sign of ∆m2

31. Observation of ∆m221 driven sub-dominant effects in

atmospheric neutrinos can be used to study the deviation of θ23 from maximalityand its octant. We showed how non-zero values of θ13 affects this measurement.At the same time non-zero θ13 drives large matter effects in atmospheric neutri-nos and these can be used to study the deviation of θ23 from maximality and itsoctant.

One needs a neutrino mass model which consistently explains all observationsof neutrino experiments. We modify the Zee mass matrix by adding a real oneparameter perturbation which is purely diagonal and trace-less. We show thatin this way we can explain both solar and atmospheric neutrino oscillation data.There is a correlation between the deviation from strict maximality of |Uµ3| =1/√

2, with the emergence of a small but non-zero Ue3. We calculate how big avalue can Ue3 get when we restrict ourselves within the allowed regions of solarand atmospheric neutrino masses and mixing angles. We also discuss the impactof a S2 permutation symmetry on our mass matrix and show how a small Ue3 6= 0can emerge when this S2 permutation symmetry between the second and thethird generation is broken.

Publications:

1. Sanjib K. Agarwalla, Sandhya Choubey, Srubabati Goswami, Amitava Ray-chaudhuri, Neutrino parameters from matter effects in in the nu(e) survival prob-ability long baselines, Phys. Rev. D 75, 097302 (2007).

2. Sanjib K. Agarwalla, Sandhya Choubey, Amitava Raychaudhuri, Neutrinomass hierarchy and theta(13) with a magic baseline beta-beam experiment, Nucl.Phys. B 771, 1 (2007).

3. Abhijit Bandyopadhyay, Sandhya Choubey, Srubabati Goswami, S.T. Pet-cov, Solar Model Parameters and Direct Measurements of Solar Neutrino Fluxes,to appear in Phys. Rev. D (2007).

4. Biswajoy Brahmachari, Sandhya Choubey, Modified Zee mass matrix withzero-sum condition, Phys. Lett. B 642, 495 (2006).

5. Sandhya Choubey, N.P. Harries, G.G. Ross, Probing neutrino oscillations fromsupernovae shock waves via the IceCube detector, Phys. Rev. D 74, 053010(2006).

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Preprints:

1. Sandhya Choubey, N.P. Harries, G.G. Ross, Turbulent Supernova Shock Wavesand the Sterile Neutrino Signature in Megaton Water Detectors, hep-ph/0703092(under review in Phys. Rev. D).

2. Sandhya Choubey, What we can learn from atmospheric neutrinos, arXiv:hep-ph/0609182.

3. Sandhya Choubey and other members of ISS physics working group, In-ternational scoping study of a future Neutrino Factory and Super-beam facility.http://www.hep.ph.ic.ac.uk/iss/wg1-phys-phen/index.html

4. Ram Lal Awasthi and Sandhya Choubey, Confusing Sterile Neutrinos withDeviation from Tribimaximal Mixing at Neutrino Telescopes, in preparation.

5. M.Sajjad Athar et al, [INO Collaboration], India-based Neutrino Observatory:Project Report


1. The XXII International Conference on Neutrino Physics and Astrophysics, USA,June 2006.

2. XII IFT-UAM/CSIC Christmas Workshop, Spain, December 2006.

3. The 17th DAE-BRNS High Energy Physics Symposium, India, December 2006.

4. 21st International Workshop on Weak Interactions and Neutrinos, India, January2007.

5. Joint Indo-German School And Workshop 2007 Neutrinos in Physics, Astrophysicsand Cosmology, February 2007.


1. University of Oxford, Oxford, United Kingdom, May to August, 2006.


1. What We Can Learn from Atmospheric Neutrinos, Invited plenary talk at “TheXXII International Conference on Neutrino Physics and Astrophysics”, SantaFe, New Mexico, USA, June 13-19, 2006.

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2. Neutrino Phenomenology: Current status and future prospects, Invited plenarytalk at “XII IFT-UAM/CSIC Christmas Workshop, Madrid, Spain, December18-20, 2006.

3. Atmospheric neutrinos: What more can we learn?, Invited plenary talk at “The17th DAE-BRNS High Energy Physics Symposium”, IIT, Kharagpur, Decem-ber 11-15, 2006.

4. Neutrino Physics: Future Directions, Invited talk at “21st International Work-shop on Weak Interactions and Neutrinos”, SINP, Kolkata, January 15-20,2007.

5. Neutrino Oscillation Phenomenology, Lecture series at “Joint Indo-GermanSchool And Workshop 2007 Neutrinos in Physics, Astrophysics and Cos-mology”, TIFR, Mumbai, February 12-23, 2007.

6. Supernova Shock Waves and Sterile Neutrinos, Invited talk at “Joint Indo-GermanSchool And Workshop 2007 Neutrinos in Physics, Astrophysics and Cos-mology”, TIFR, Mumbai, February 12-23, 2007.

7. Neutrino Physics, Lecture series at “INO Training School”, HRI, Allahabad,India, April 10-25, 2006.

Other Activities:1. Organizing schools/conferences:

(a) Co-organizer of the Ino Training School at HRI, Allahabad, April, 2006.(b) Co-ordinator of the neutrino physics, astroparticle and cosmology work-

ing group at WHEPP X, to be held at Chennai, January, 2008.(c) Member of the organizing committee of the Neutrino Meeting to be

held at HRI, February, 2008.

2. Teaching at HRI: Gave a special course on ‘Statistical Modeling of Data andError Analysis in HEP’, March-May, 2006.

3. Mentoring Project Students: Guided Ram Lal Awasthi on the project, ‘SolarNeutrino Problem and its Solution’, October-November 2006.

4. Reviewing Papers: Refereed papers for

(a) Physical Review Letters(b) Physical Review D(c) Journal of High Energy Physics(d) Physica Scripta.

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5. Talks at HRI:

(a) Solving the degeneracy of the lepton-flavor mixing angle thetaatm by theT2KK two detector neutrino oscillation experiment, pheno-lunch on Novem-ber 11, 2006.

(b) Neutrino Physics: Future Directions, HRI Internal Symposium, March2007.

6. Committees Served:

(a) Office and Furniture Committee (member)

(b) Rajbhasha Committee (member)

(c) Guest House and Pantry (member, convenor for a period of 4 months)

(d) HRIRA (chair-person)

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69

Tapas Kumar Das

Research Summary:


1. Topological Hamiltonian dynamics.

2. Analogue gravity.

3. Accretion phenomena as an autonomous dynamical system.

4. Chaotic features of black hole accretion.

5. Galactic centre astrophysics.

6. Microblazers.

Publications:

1. Das, Tapas Kumar, Bilic, Neven, & Dasgupta, Surajit, Black-Hole AccretionDisc as an Analogue Gravity Model, Journal of Cosmology & AstroparticlePhysics, 06, 009, (2007)

2. Goswami, Sanghamitra, Khan, Saba Nasreen, Ray, Arnab Kumar, & Das,Tapas Kumar, Axisymmetric black hole accretion in the Kerr metric as an au-tonomous dynamical system, Monthly Notices of the Royal Astronomical Soci-ety, 378, 1407, (2007)

3. Mandal, Ipsita, Ray, Arnab Kumar, & Das, Tapas Kumar, Critical propertiesof spherically symmetric black hole accretion in Schwarzschild geometry, MonthlyNotices of the Royal Astronomical Society, 378, 1400, (2007)

4. Barai, Paramita & Das, Tapas Kumar, Characterizing general relativistic tran-sonic astrophysical accretion in Kerr black holes, Proceedings of the XXIII TexasSymposium on Relativistic Astrophysics, Melbourne, Australia, 11th - 15th

December, 2006, To Appear, (2007)

5. Chaudhury, Soumini, Ray, Arnab Kumar, & Das, Tapas Kumar, Critical prop-erties and stability of stationary solutions in multi-transonic pseudo-Schwarzschildaccretion, Monthly Notices of the Royal Astronomical Society, 373, 146, (2006)

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Preprints:

1. Bilic, Neven, Das, Tapas Kumar, & Ray, Suhrita, Analogue gravity effects inpseudo-Schwarzschild shocked accretion disc, (Submitted).

2. Bhattacharaya, Atri, Ray, Arnab Kumar, Bhattacharjee, Jayanta Kumar, Das,& Tapas Kumar, Critical dynamics of quasi-viscous transonic black hole accretion,(In preparation).

3. Moscibrodzka, Monica, Das, Tapas Kumar, & Czerny, Bozena, On determi-nation of the spin of the Galactic centre black hole, (In preparation).

4. Dasgupta, Surajit, Das, Tapas Kumar, & Rao, A. R., Possible identification ofCygnus X-3 as a Galactic microblazar, (In preparation).

5. Das, Tapas Kumar, & Czerny, Bozena, Chaotic features of multi-transonicityand its effects on microvariability, (In preparation).


1. Presidency College, Calcutta, India, February, 2007.

2. PRL, India, August - September, 2006 & February, 2007.

3. IACS, India, December, 2006.

4. Visva Bharati University, India, December, 2006.

5. Burdwan University, India, December 2006.

6. TIARA, Taiwan, March - May 2006.

7. NCU, Taiwan, April, 2006.


1. Accretion processes onto astrophysical black holes, Presidency College, Calcutta,February, 2007.

2. Black hole accretion as dynamical systems, a multi-lecture course in the ThirdSERC School on Non-linear Dynamics, December 4th - 23rd, 2006, IndianAssociation for Cultivation of Science, Calcutta, India.

3. On the current trend in research in astrophysical science, orientation course atBurdwan University, Burdwan, India, December, 2006.

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4. What is black hole accretion?, popular science lecture at Burdwan University,Burdwan, India, December, 2006.

5. Astrophysics around black hole, popular science lecture at Visva Bharati Uni-versity, Santiniketan, India, December, 2006.

6. Transonic Properties of Relativistic Accretion, PRL, India, August, 2006.

7. Black Hole Astrophysics, colloquium at National Central University, Taiwan,April, 2006.

8. Transonic properties of astrophysical accretion, colloquium at Academia Sinica,Taiwan, April, 2006.

9. Dependence of relativistic accretion on black hole spin, Academia Sinica, Taiwan,April, 2006.

Other Activities:


(a) May - June 2006

i. Saba Nasreen Khan, M.Sc. 1st year, IIT Delhi.ii. Atri Bhattacharya, M.Sc. 1st year, IIT Bombay.

iii. Suhrita Ray, M.Sc. 1st year, IIT Bombay.iv. Sanghamitra Goswami, M.Sc. 1st year, IIT Bombay.

(b) Sept - Oct. 2006:

i. Tanushree Basu, M.Sc. 1st year, Calcutta University.

Several manuscripts, co-authored with the above students, are accepted/submitted/under preparation, see list of publications for further detail.

2. Teaching & Lecture Course:

(a) Taught ‘Classical Mechanics’ at HRI graduate school (Aug. - Dec.) in2006. I developed this course as ‘Mechanics on manifold’, which dealswith a study of Lagrangian and Hamiltonian dynamics on manifold,using the framework of differential geometry and topology.

(b) A lecture course on Black hole accretion as dynamical systems, a multi-lecture course in the Third SERC School on Non-linear Dynamics, De-cember 4th - 23rd, 2006, Indian Association for Cultivation of Science,Calcutta, India.

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3. Reviewing papers: Served as the referee for the following papers:

(a) Two papers submitted to the Classical and Quantum Gravity.

(b) Two papers submitted to the Astrophysical Journals.

(c) One paper submitted to the Monthly Notices of the Royal AstronomicalSociety.

4. Journal Club Review Talk & HRI Internal Seminar:

(a) See a black hole on a shoestring, Journal Club talk, November, 2006.

(b) Analogue Gravity Phenomena, HRI internal symposium, March, 2007.


(a) Served as a member in the computer committee (till 31st July, 2006).

(b) Serving as a member of the Sports and Entertainment Committee andthe Medical Committee from 1st August, 2006.

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73

AseshKrishna Datta

Research Summary:


1. Issues involved in interpretation of forthcoming data from the Large HadronCollider (LHC)

2. Phenomenology of CP-violating (CPV) Supersymmetric (SUSY) models

3. Collider studies of high-scale nonuniversalities in SUSY spectrum

4. Alternate scenarios (mechanisms) of Electroweak Symmetry Breaking (EWSB)and their collider phenomenology

5. Phenomenology of Extra Dimensional Models

Preprints: (In preparation)

1. Minimal Universal Extra Dimensions in CalcHEP/CompHEP, with K. Kong andK.T. Matchev,

2. On implications of high-scale nonuniversalities of gaugino masses at LHC, with S.Bhattacharya and B. Mukhopadhyaya

3. On interesting signatures of CP-violating SUSY at LHC, with A. Datta, P. Ban-dopadhyay and B. Mukhopadhyaya

4. On novel signatures of Little Higgs scenario (with T-parity) at LHC, with P. Dey,S.K. Gupta, B. Mukhopadhyaya and A. Nyffeler


1. IACS, Kolkata, January, 2007

2. Participated in Strings To LHC, an international conference organised byTIFR and held at Goa in January, 2007

3. Participated in Weak interactions and Neutrinos, an international conferenceheld at SINP, Kolkata in January, 2007

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1. Collider Searches for Extra Dimensions at the Workshop on LHC Physics, TIFR,Mumbai, September, 2006

2. Spin Information at the LHC at the Topical Meeting on Physics at the LHC,HRI, Allahabad, December, 2006

Other Activities:


(a) During the period I offered reading course (project) on the Basics ofCollider Physics to one of our young students who later joined the phe-nomenology group for her Ph.D.

(b) A visiting consultant/student has been working with me for last 8months on building up and streamlining the computing facilities usedby the collider group here at HRI. We have already met a few targetswhile working with a broader goal and a few projects are to be finishedsoon.

2. Reviewing papers:

Served as a referee for the following journals:

(a) One paper submitted to the Physics Letters B

(b) One paper submitted to the Indian Journal of Physics

3. HRI Internal Seminar:

Warming Up for the LHC, HRI internal symposium, March, 2007.


(a) Serving as a member in the Computer Committee

(b) Serving as a member in the Sport and Entertainment Committee

5. Organizing Workshops/Conferences/Schools etc.:

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(a) Organized the Topical Meeting on Physics at the LHC (with interna-tional participation) along with my HRI colleagues in December, 2006

(b) Serving as one of the conveners for the Xth Workshop on High EnergyPhysics Phenomenology (WHEPP-X, with international participation)to be held at Chennai, India during January, 2008

(c) Organizing a Pedagogical School on QCD at HRI in November, 2007along with my colleagues from HRI

6. Project RECAPP:

The other group-effort in which I have been taking immense interest anddevoting time is towards having a concrete planning for the proposed Re-gional Centre for Accelerator-based Particle Physics (RECAPP). The projectis now technically granted and started functioning in April, 2007. The run-ning of the Centre in full swing which envisages a vigorous visitors’ pro-gramme requires quite a few technical and academic issues to be addressedimmediately. As the technical coordinator of the Centre I am now pursuingthem.

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76

Justin R. David

Research Summary:

My research during 2006-2007 has been centered on two distinct aspects of stringtheory: i) Understanding the gauge/string duality in regimes where the stringtheory is strongly coupled while the gauge theory is free. ii) The study of thespectrum of dyonic states in certain class of string compactifications with N = 4supersymmetry.

On the topic of gauge/string duality, in collaboration with R. Gopakumar andthe group at the Weizmann Institute we continued to investigate properties of theworldsheet conformal field theories which are conjectured to be dual to free largeN gauge theories. These conformal field theories are constructed using the map-ping of Feynman diagrams to the worldsheet suggested by R. Gopakumar. Themodular invariance of these CFT’s is shown to be built into the formalism. Weshow that correlation functions in these CFT’s which are localized on subspacesof moduli space may be interpreted as delta-function distributions, and that thiscan be consistent with a local worlsheet description given some constraints onthe operator product expansion coefficients.

In collaboration with D. Jatkar and A. Sen we obtained the spectrum of a class ofquarter BPS dyons in a generic N = 4 supersymmetric ZN orbifold of type IIAstring theory on K3 × T 2 or T 6. We also find the asymptotic expansion of thestatistical entropy to the first non-leading order in inverse power of charges andshow that it agrees with the entropy of a black hole carrying same set of chargesafter taking into account the effect of the four derivative Gauss-Bonnet term inthe effective action of the theory. At present we are extending these methods toobtain the spectrum of BPS dyons in N = 2 compactifications.

Publications:

1. Justin R. David, Ashoke Sen, CHL Dyons and Statistical Entropy Function fromD1-D5 System, JHEP 0611 072, (2006).

2. Justin R. David, Rajesh Gopakumar, From spacetime to worldsheet: Four pointcorrelators, JHEP 0701 063, (2007).

3. Justin R. David, Dileep P. Jatkar, Ashoke Sen, Dyon Spectrum in N = 4 Su-persymmetric Type II String Theories, JHEP 0611 073, (2006).

4. Justin R. David, Dileep P. Jatkar, Ashoke Sen, Dyon spectrum in genericN = 4supersymmetric ZN orbifolds, JHEP 0701 016, (2007).

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Preprints:

1. Ofer Aharony, Justin R. David, Rajesh Gopakumar, Zohar Komargodski ,Shlomo S. Razamat, Comments on worldsheet theories dual to free large N gaugetheories hep-th/0703141.


1. Indian strings meeting, India, December, 2006.


1. Tata Institute of Fundamental Research, Mumbai, India, April 2006.

2. Abdus Salam International Centre for Theoretical Physics, Trieste, Italy, April-June 2006.

3. Utrecht University, Utrecht, The Netherlands, May 2006.

4. CERN, Geneva, Switzerland, June 2006.

5. Indian Institute of Technology, Kanpur, India, February 2007.

6. Weizmann Institute of Science, Rehovot, Israel, February 2007.


1. Towards a string bit formulation of N = 4 super Yang-Mills, String theory andmathematical physics seminar, TIFR, Mumbai, April 2006.

2. On the dyon partition function in N = 4 string theories, High energy theoryseminar, ASICTP, Trieste, May 2006.

3. On the dyon partition function in N = 4 string theories, String theory seminar,Utrecht University, Utrecht, May 2006.

4. On the dyon partition function inN = 4 string theories, Theory seminar, CERN,Geneva, June 2006.

5. From spacetime to worldsheet: Four point correlators, Lecture at Indian stringsmeeting, Puri, December 2006.

6. Black hole entropy in string theory, Physics colloquium, IIT, Kanpur, February2007.

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7. From spacetime to worldsheet: Four point correlators, Physics seminar, IIT, Kan-pur, February 2007.

8. On the dyon partition function in N = 4 string theories, String theory seminar,Weizmann Institute of Science, Rehovot, February 2007.

Other Activities:

1. Teaching Mathematical Methods-I, August-December, 2006.

2. Supervised string project:Supersymmetry, January-March, 2007.

3. Member of national organizing committee: Indian strings meeting, Decem-ber 2006.

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79

Paramita Dey

Research Summary:

My current research interest is:

Phenomenology of the Standard Model and Beyond (Extra Dimension, LittleHiggs Models, Higgs Triplets in Standard Model etc.).

Preprints:

1. Paramita Dey, Asmaa Abada, Gregory Moreau: Neutrinos in flat extra dimen-sion: towards a realistic scenario hep-ph/0611200 (communicated to JHEP)

2. Paramita Dey, Ritesh Singh: Top quark polarization as a probe of extra dimension(in preparation)

3. Paramita Dey, Asesh Dutta, Sudhir K Gupta, Andreas Nyffeler, BiswarupMukhopadhyaya: Distinguishing the Little Higgs model with T-parity fromSupersymmetry at the LHC (in preparation)

4. Paramita Dey, Biswarup Mukhopadhyaya, Anirban Kundu: Some Phenomeno-logical Aspects of a Doublet-Triplet Higgs Model (in preparation)


1. Topical Meeting on Physics at the LHC, India, December, 2006,

2. International Workshop on Weak Interactions and Neutrinos (WIN07), India, Jan-uary, 2007.


1. Neutrinos in Flat Extra Dimension: Towards a Realistic Scenario / talk, Inter-national Workshop on Weak Interactions and Neutrinos (WIN07), SINP,Kolkata, January 2007.

Other Activities:

1. Obtained Ph.D. Degree, December, 2006.

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Raj Gandhi

Research Summary:


1. Matter Effects in Atmospheric Neutrinos

2. Physics issues with a Neutrino Factory

3. Physics Potential of INO

4. Ultra-high Energy Cosmic Ray Muons

Publications:

1. R. Gandhi and S. Panda, “Probing the cosmic ray ’knee’ and very high en-ergy prompt muon and neutrino fluxes via underground muons,” JCAP0607, 011 (2006) [arXiv:hep-ph/0512179].

2. R. Gandhi and W. Winter, “Physics with a very long neutrino factory base-line,” Phys. Rev. D 75, 053002 (2007) [arXiv:hep-ph/0612158].

3. R. Gandhi et al., “Working Group Report: Astroparticle And Neutrino Physics,”Pramana 67, 735 (2006).

Preprints:

1. M. S. Athar et al. [INO Collaboration], “India-based Neutrino Observatory:Project Report. Volume I,”

2. The ISS Physics Working Group, ”Physics at a Future Neutrino Factory andbeta-beam Facility” in preparation, current draft at http://www.hep.ph.ic.ac.uk/

3. R. Gandhi, P. Ghoshal, S. Goswami, P. Mehta, S. Uma Sankar & S. Shal-gar, Mass Hierarchy Determination in future Atmospheric Neutrino Detectors,(In preparation).


1. TIFR, April 2006.

2. Institute for Advanced Studies, Princeton, May 2006.

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Invited Talks, Seminars and Colloquia:

1. Physics with the Indian Neutrino Observatory, School of Natural Sciences Col-loquium, TIFR, April 2006.

2. Probing Very High Energy Cosmic Ray Muons, Theory Seminar, TIFR, April2006.

3. Very High Energy Cosmic Ray Muon Detection, Talk at PHENO 06, Madison,May 2006.

4. Physics Potential of INO, Invited Talk at ”Next Generation Neutrino and Nu-cleon Decay Detectors” Seattle, September, 2006.

5. Physics With a Very Long Baseline, Talk at ”Weak Interactions and NeutrinoPhysics ” (WIN07) Kolkata , January, 2007.

6. Some Physics Issues with a Very Long Neutrino Factory baseline, Talk at ”JointIndo-German School and Workshop” (JIGSAW 07) at TIFR, February 2007.

7. Physics Potential of INO, Talk at ”INO Meeting for Universities” Delhi, March,2007.

Other Activities:

1. Indian Co-ordinator (along with S. Uma Sankar) for the Physics Group of theInternational Scoping Study for a Future neutrino Factory and Beta beamFacility

2. Member, Program Management Commitee, Indian Neutrino Observatory

3. Teaching & Lecture Course: ‘Electrodynamics’ at HRI (Aug. - Dec.) in 2006.

4. Referee for Physical Review Letters and Pramana

5. Member, Medical, Security and Housing Allocation Commitees

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82

Debashis Ghoshal

Research Summary:

The p → 1 limit of p-adic string theory was revisited from the perspective of theworldsheet. It was argued that string theory based on the p-adic field providesa discretisation of the bosonic string worldsheet. Those based on its algebraicextensions of increasing degree make this approximation better leading to a con-tinuum limit in the sense of the renormalisation group.

A q-deformation of the arithmetic analogue of Veneziano amplitude was pro-posed using the q-extended p-adic gamma function. This provides a one param-eter deformation of the arithmetic Veneziano amplitude. Difficulties with gener-alising this construction to higher amplitudes were discussed.

The notion of generalised hyperKahler structure in the context of string theorywas discussed. An explicit example was provided and a sketch towards furthergeneralisation was outlined.

Publications:

1. D. Ghoshal, p-Adic string theories provide discretization to the ordinary stringworldsheet, Phys. Rev. Lett. 97, 151601, (2006).

2. B. Ezhuthachan and D. Ghoshal, Generalised HyperKahler Manifolds in StringTheory , J. High Energy Phys.04, 083, (2007).

3. D. Ghoshal, p-Strings vs. strings, in Mathematical Physics: Proceedings ofthe 12th Regional Conference, Islamabad, Pakistan, 2006, Eds. M. JamilAslam et al, World Scientific (2007).

Preprints:

1. D. Ghoshal, Quantum extended arithmetic Veneziano amplitude, HRI-P-0604001,AEI-2006-036, math-ph/0606003.


1. 12th Regional Conference in Mathematical Physics, Islamabad, Pakistan, April2006.

2. Indian String Meeting (ISM 06), Puri, India, December 2006.

3. From Strings to LHC, Goa, India, January 2007.

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1. Albert Einstein Institute, Potsdam, Germany, April–June 2006,

2. Tata Institute of Fundamental Research, Mumbai, India, November 2006 –February 2007.


1. p-Strings vs. strings, 12th Regional Conference in Mathematical Physics, Na-tional Centre for Physics, Quaid-e-Azam University, Islamabad, Pakistan,April 2006.

2. p-Toying with strings, seminars at the Delhi University, Delhi, JawaharlalNehru University, New Delhi and University of Hyderabad, Hyderabad,October & November 2006.

3. p-String theory as discretisation of the string worldsheet, Theoretical PhysicsColloquium, Tata Institute of Fundamental Research, Mumbai, February 2007.

Other Activities:

1. Supervised the projects of two visiting students, July–August 2006.

2. Mathematical aspects of compactification, a special topics course (of half-semesterduration) in the Graduate School Curriculum at HRI, August–October 2006.

3. Member of the Planning Committee of the SERC Schools in TheoreticalHigh Energy Physics.

4. Associate Editor, General Relativity & Gravitation, since January 2007

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Rajesh Gopakumar

Research Summary:

In the last year, I have continued to build on my attempts to reconstruct the stringworldsheet theory dual to free large N Yang-Mills theory. In work with JustinDavid, we obtained the explicit form of the worldsheet correlators for a specialclass of field theory correlators. The explicit form exhibited a number of prop-erties expected of worldsheet correlators such as manifest crossing symmetry.The precise form of the answer also shows potentially interesting connections tocorrelators of the 2d Ising model. In work with O. Aharony, J. David, Z. Komar-godsky and S. Razamat, we studied another aspect of the worldsheet correlatorswhich arises in the case of certain free field diagrams. This is the issue of locali-sation on moduli space of the corresponding worldsheet correlators. We studiedhow this arises in some detail and found an interesting connection between thelocalisation on moduli space and the lack of space-time contractions between thecorresponding field theory operators. We are continuing to investigate these andother aspects in trying to learn some general lessons about the worldsheet theory.

Another strand of research has been to study black holes in Anti-de Sitter spacesusing the gauge-gravity duality. With Suvankar Dutta we tried to see how themembrane paradigm might be realised in the specific context of the AdS/CFTduality for black holes in AdS spaces. We have also been studying the physicsof charged black holes in AdS5 with the hope of quantitatively comparing thethermodynamics of near extremal black holes at weak and strong coupling.

Publications:

1. J. R. David and R. Gopakumar, From spacetime to worldsheet: Four point corre-lators JHEP 0701, 63 (2007).

2. S. Dutta and R. Gopakumar, On Euclidean and Noetherian entropies in AdSspace Phys. Rev. D 044007, (2006).

3. R. Dijkgraaf, R. Gopakumar, H. Ooguri and C. Vafa, Baby universes and stringtheory, Conference Proceedings of Workshop on Einstein’s Legacy, ToshaliSands. Int. J. Mod. Phys. D.15, 1581, (2006).

Preprints:

1. O. Aharony, J. David, R. Gopakumar, Z. Komargodsky and S. Razamat,Comments on worldsheet theories dual to free large N gauge theories (hep-th/0703141,to appear in Phys. Rev. D.).

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1. MSRI program on ”New Topological Structures in Physics”, Berkeley, USA, May2006.

2. Strings 2006, Beijing, China, June 2006.

3. Ahrenshoop Symposium, Berlin, Germany, Sep. 2006.

4. 24th IAGRG Meeting, Delhi, Feb. 2007.


1. Harvard University, USA, Apr. 2006.

2. University of California, Berkeley, May 2006.

3. University of California, Santa Barbara, USA, May 2006.

4. TIFR, Mumbai, Jun. 2006.

5. IISc, Bangalore, Mar. 2007.

6. IISER, Kolkata, Feb., Mar. 2007.


1. From Spacetime to Worldsheet, Duality Seminar, Harvard University, USA,Apr. 2006.

2. From Spacetime to Worldsheet, String Seminar, University of California, Berke-ley, USA, May 2006.

3. From Spacetime to Worldsheet, String Seminar, University of California, SantaBarbara, USA, May 2006

4. Strebel Differentials and String Theory, Talk at Conference on New Develop-ments in Gromov-Witten Theory. MSRI USA, May 2006.

5. Three Lecture Series Tea-duality seminars TIFR Mumbai. Jun. 2006.

6. Strebel Differentials and String Theory, Joint Mathematics- Physics ColloquiumTIFR, Mumbai, Jun. 2006.

7. From Spacetime to Worldsheet, Plenary Talk Strings 2006 Beijing, Jun. 2006.

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8. From Spacetime to Worldsheet, Ahrenshoop Symposium Berlin, Germany Sep.2006.

9. New Perspectives on Gravity from Gauge-String Duality Plenary Talk, IAGRG-24, Jami Millia, Delhi, Feb. 2007.

10. From Fields to Strings Physics Colloquium IIScBangalore, Mar. 2007.

11. Mini course on Extremisation Principles in Physics IISER Kolkata, Feb., Mar.2007.

Academic recognition/Awards:

• ICTP Prize, 2006.

• Swarnajayanthi Fellowship, 2006.

Other Activities:

1. Delivered popular lecture on Spacetime and String Theory at Techkriti 07, IIT,Kanpur, Feb. 2007.

2. Guided three VSP students, Oct. 2006.

3. Organised with other members of the String group, Informal workshop onString theory, Dec. 2006.

4. Member of various administrative committees.

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Manoj Gopalakrishnan

Research Summary:

1. Signal transduction in cells

The binding of extra-cellular ligands by cell surface receptors is the first stepin signal transduction. Since the number of receptors is often not too large,stochastic concepts are of value in quantitatively understanding this inter-action. We have recently developed a self-consistent stochastic formalismfor studying reversible ligand association to receptors on a spherical cellsurface.The complete time-dependence of the ligand-bound receptor frac-tion is calculated. Contrary to the commonly accepted view, we find thatthe effective association rate changes non-monotonically as a function oftime, and equals its intrinsic biochemical value at early as well as late times.In an intermediate regime, the well-known Berg-Purcell scaling is satisfied.On the experimental side, this implies the existence of two time-scales forthe binding curve. Investigations of the implications of this results for gra-dient detection in bacterial chemotaxis are currently being pursued.

2. Noise and response in a sensory module

Noise in transduction mechanisms can often interfere with signal percep-tion in sensory systems. A new generating functional formalism has beendeveloped to study the stochastic kinetics of a signaling module with neg-ative feedback (as occurs in many sensory systems). The principal com-ponents of such a module are (i) an ion channel that switches randomlybetween open and closed conformations, and (ii) a negative feedback effectwhereby the incoming ions increases the closing rate of the channel. An-alytical results for a single module have been calculated within perturba-tion theory to second order in feedback strength and to first order in 1/λ,where λ is the intrinsic time-scale of regulation of ion concentration insidethe module. Efforts are currently on to generalize the formalism to includeseveral spatially connected modules with diffusion of ions between them.

Publications:

1. Manoj Gopalakrishnan, Peter Borowski, Martin Zapotocky and Frank Julicher,Response and fluctuations of a two-state signaling module with feedback, Phys.Rev. E (2007, in press)

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Preprints:

1. Shivam Ghosh, Manoj Gopalakrishnan and Kimberly Forsten-Williams, Self-consistent stochastic theory of reversible ligand binding to a spherical cell surface(inpreparation).

2. Bindu Govindan, Manoj Gopalakrishnan and Debashish Chowdhury En-hanced depolymerization of microtubules by MCAK proteins,(in preparation).


1. Modeling infectious diseases: From cell to society, Institute of Mathematical Sci-ences, Chennai, India, September 2006.

2. STATPHYS-KOLKATA VI, Saha Institute of Nuclear Physics, Kolkata, India,January 2007.


1. Institute of Mathematical Sciences, Chennai, India, July 2006.

2. Indian Institute of Technology Kanpur, Kanpur, India, August 2006.


1. Response and fluctuations of a signaling module with negative feedback, Instituteof Mathematical Sciences, Chennai, July 2006.

2. Theory of ligand binding to cell membrane surfaces, Department of Physics, IITKanpur, August 2006.

3. Stochastic theory of ligand binding to a spherical surface: How a bacterium livesbetter and longer by eating less,STATPHYS-KOLKATA VI,Saha Institute of Nu-clear Physics, Kolkata, January 2007.

Other Activities:

1. Teaching:

‘Statistical Mechanics’ for HRI graduate students (January-May 2007).

2. Other lectures:

(a) Two lectures on stochastic processes for VSP students at HRI (May2006).

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(b) Popular lecture on ‘Lipid rafts and cell signaling’ at Science Club Meet-ing, Institute of Mathematical Sciences, Chennai (July 2006).

(c) HRI internal symposium lecture: How a bacterium can survive better byeating less(March 2007).

3. Mentoring students:

(a) I supervised the research projects of these students in the CondensedMatter Visiting Students Program (VSP).

i. Shivam Ghosh, St. Stephen’s College, Delhi(May-June 2006)

ii. Abhishek Mukhopadhyay, IIT Kanpur(May-June 2006)

iii. Arnab Banerjee, Jadavpur University(September 2006)

iv. Jonathan Dawson, Allahabad Agricultural Institute-DU(November-December 2006)

(b) Supervised the term paper/course project in Statistical Mechanics (M.Sc 2nd year, IIT Kanpur) of Abhishek Mukhopadhyay (August-December2006), Title: Effect of solution receptors in dissociation of ligands bound tosurface receptors.

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Srubabati Goswami

Research Summary:

Our understanding of neutrino properties have progressed impressively over thelast decade owing to outstanding results from solar, atmospheric, reactor andaccelerator based neutrino oscillation experiments. In the past year, we exploreda novel possibility of determining the solar model parameters, which serve asinput in the calculations of the solar neutrino fluxes, by exploiting the data fromdirect measurements of the fluxes. More specifically, we use the rather precisevalue of the 8B neutrino flux, φB obtained from the global analysis of the solarneutrino and KamLAND data, to derive constraints on each of the solar modelparameters on which φB depends. We also use more precise values of 7Be andpp fluxes as can be obtained from future prospective data and discuss whethersuch measurements can help in reducing the uncertainties of one or more inputparameters of the Standard Solar Model.

We also studied the large matter effects encountered by the electron neutrinospassing through the earth and its effect νe → νe survival probability for certainranges of energies and pathlengths. These can be used to determine the the signof the atmospheric neutrino mass squared difference, ∆31, and the third leptonicmixing angle. θ13 using beta beams as sources for pure νe/νe beams.

One very interesting mixing scheme, which is compatible with all neutrino os-cillation data, is tri-bimaximal mixing . We study corrections to tri-bimaximalneutrino mixing from both renormalization running and from the Planck scale.We show that Planck scale effects can modify the mixing angles in the oppo-site direction than renormalization. Therefore, the usual constraints on neutrinomasses, Majorana phases or tan β stemming from renormalization running argu-ments can be relaxed or even removed. This will be true for any neutrino mixingscheme. Consequently, since in the Standard model there is hardly any running,sizable corrections due to Planck scale effects can nevertheless be there. In par-ticular, for a neutrino mass of 0.4 eV, the correction to sin2 θ12 − 1

3can be up to

15%. We show further that for tri-bimaximal mixing the “unphysical phases” inthe neutrino mass matrix are crucial for the flavor-blind Planck scale effects, sincewithout them the mixing angles will not change at all.

Publications:

1. A. Bandyopadhyay, S. Choubey, S. Goswami and S. T. Petcov , Solar modelparameters and direct measurements of solar neutrino fluxes, Phys. Rev. D 75,093007, (2007)

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2. S. K. Agarwalla, S. Choubey, S. Goswami and A. Raychaudhuri, Neutrinoparameters from matter effects in Pee at long baselines, Phys. Rev. D 75, 097302(2007)

3. A. Dighe, S. Goswami and W. Rodejohann Corrections to Tri-bimaximal Neu-trino Mixing: Renormalization and Planck Scale Effects, Phys. Rev. D 75, 073023(2007)

4. R. Gandhi et al., Working Group Report: Astroparticle And Neutrino Physics,Pramana, 67, 735 (2006).

5. S. Goswami Physics potentials of a magnetized iron calorimeter detector, Phys.Scripta T127, 28 (2006).

6. S. Goswami and W. Rodejohann Constraining mass spectra with sterile neutri-nos from neutrinoless double beta decay, tritium beta decay and cosmology Phys.Rev. D 73, 113003 (2006).

7. A. Dighe, S. Goswami and P. Roy Quark-lepton complementarity with quaside-generate Majorana neutrinos, Phys. Rev. D 73, 071301 (2006)

Preprints:

1. M. S. Athar et al. [INO Collaboration], A Report of the INO Feasibility Study.Updated from the earlier Interim Report of May 1, 2005,

2. Srubabati Goswami and Werner Rodejohann MiniBooNE Results and Neu-trino Schemes with 2 sterile Neutrinos: Possible Mass Orderings and Observablesrelated to Neutrino Masses, in preparation

3. Srubabati Goswami and Toshihiko Ota, Testing Non-Unitarity of NeutrinoMixing Matrices in Neutrino Factories, (in preparation)

4. Raj Gandhi, Pomita Ghoshal, Srubabati Goswami, Poonam Mehta, S UmaSankar, Shashank Shalgar Mass Hierarchy determination via future AtmosphericNeutrino Detectors in preparation


1. 2nd Scandinavian Neutrino Workshop , Sweden, May 2006,e.g. January, 2007

2. WIN07, India, January 2007.

3. Joint Indo-German School And Workshop 2007, India, February 2007.

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1. Techniche Universitaet Muenchen, Germany April -August 2006

2. Physical Research Laboratory, Ahmadabad, December 2006-January 2007

3. Max–Planck–Institut fur Kernphysik, Heidelberg, Germany, May-June 2007.


1. Physics Potentials of a magnetized iron calorimeter detector , , University ofStockholm Sweden, May, 2006.

2. Earth matter effect at very long-baselines , TPSC Seminar, Physical ResearchLaboratory , , December 2006.

3. Neutrino Physics-Theory, Summary talk for the Neutrino Physics working group,WIN07, Saha Institute Of Nuclear Physics, January 2007

4. Neutrino Physics : An introduction, SERC School lecture Jammu University,Jammu, February 2007.

5. The Jigsaw of Neutrino Masses and Mixing, TIFR, Mumbai, February 2007.

6. Radiatively Broken Symmetries of Neutrinos, Max-Planck Institute, Heidelberg,June 2007.


• National Academy of Science P. Sheel Young Women Scientist Award.

Other Activities:

1. Partial Supervision of thesis work of Pomita Ghoshal

2. Working group co-ordinator, WIN07, January, 2007.

3. Refereeing papers for PRD, PLB.

4. Served in the Transport Committee (as convener) and Local Work Commit-tee (as member).

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Bindu S. Govindan

Research Summary:

The motor proteins MCAK belonging to the kinesin-13 family are crucial for reg-ulating microtubule dynamics during cell division. Recent experimental obser-vations have shown that MCAK uses surface diffusion on the microtubule as aneffective way to enhance the rate of its binding to the microtubule ends, thus in-ducing its depolymerization. We have developed a mathematical model of thisprocess based on the dynamical instability mechanism and random walk the-ory. Our theory shows how the kinetic parameters are modified by the action ofMCAK and the predictions are verified against experimental results.

The search, capture and segregation of chromosomes by microtubules during celldivision is a fascinating process. The central question of how microtubules ac-complish this task within a reasonable time scale, to a high degree of precision,is still unanswered to a large extent. A systematic study of this problem usingstochastic dynamics and numerical simulations is currently being pursued.

Preprints:

1. Bindu S Govindan, Manoj Gopalakrishnan, Debashis Chowdhury Enhanceddepolymerization of microtubules by MCAK proteins (in preparation)


1. Modeling infectious diseases: From Cell to Society, Institute of MathematicalSciences, Chennai, India, September 2006.


1. Indian Institute of Technology Kanpur, Kanpur, India, August 2006.


• DST Fast-Track Young Scientist Fellowship, 2006.

• Selected for short term visit to the Statistical Physics and Condensed Mattergroup, ICTP, Trieste, Italy, 2007.

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94

Harvinder Kaur Jassal

Research Summary:

The present day acceleration of the universe has been described by the presence ofdark energy, typically a cosmological constant or a scalar field. In the absence ofsignificant spatial variation in the dark energy, the key difference between scalarfield models and the one with the cosmological constant is that, in general, theequation of state of dark energy is a function of redshift in the former. It has beenknown for some time that supernova observations and constraints from structureformation can be combined to put stringent limits on models for dark energy.Several attempts have been made in the past to constrain the equation of state fordark energy, along with other cosmological parameters, using the observationsof galaxy clustering, temperature anisotropies in the CMBR and the high redshiftsupernova. We focus exclusively on constraining the variation of equation of statefor dark energy by using a combination of such observations. In particular, westudy the effect of a varying equation of state on the angular power spectrum ofthe CMBR fluctuations. We demonstrate that the combination of WMAP observa-tions and high redshift supernova observations is a very powerful constraint onvariations in dark energy, certainly more powerful that either of the observationsused in isolation.We demonstrate that the recently released high redshift supernova data from theSNLS (SuperNova Legacy Survey) project is in better agreement with CMB ob-servations, unlike the earlier data sets which preferred a different class of modelsaltogether. The SNLS data set favours models similar to the ΛCDM model. Weillustrate that WMAP observations are, by far, the strongest constraint on modelswith a varying equation of state parameter for the dark energy component in a flatuniverse. Further, the better quality of observations of temperature anisotropiesin the CMB are less susceptible to systematic effects and this makes it a morereliable probe of cosmological parameters and dark energy.The above approach is for generic models which can be parameterised, clearly insuch an approach all the details of a specific model cannot be included and theconclusions are of a more general nature. I am presently working on applyingthe methods developed here to a particular class of models, e.g., the quintessencemodels, to make definitive statements on their viability. Details like including theperturbations in dark energy that cannot be studied in the general approach canbe analysed here.During the last few years, exact solutions that describe black holes that are boundto a two-brane in a four dimensional anti-de Sitter bulk have been constructed.In situations wherein there is a negative cosmological constant on the brane, forlarge masses, these solutions are exactly the rotating BTZ black holes on the brane

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and, in fact, describe rotating BTZ black strings in the bulk. We evaluate thecanonical entropy of a free and massless scalar field (at the Hawking tempera-ture) around the rotating BTZ black string using the brick wall model. In thismethod it is assumed that quantum modes do not propagate within a ’brick wall’just outside the horizon hence doing away with the divergent coefficient of sur-face area. It is shown that the proper distance between the horizon and the ul-traviolet cut off is independent of the mass and the angular momentum of theblack hole. The rotating black hole has radiant and superradiant modes with thesuperradiant modes providing the sub-leading order contribution to entropy. Weexplicitly show that the Bekenstein-Hawking ‘area’ law is satisfied both on thebrane as well as in the bulk.

Publications:

1. H. K. Jassal, L. Sriramkumar, Entropy of BTZ black strings using the brick-wallapproach, Class. Quantum Grav. 24, 2589 (2007).


1. Advanced Topics in Data Analysis in Cosmology and Gravitational WaveAstronomy, Inter-University Centre for Astronomy and Astrophysics Ref-erence Centre Workshop, University of Delhi, India, October, 2006.

2. XXV meeting of the Astronomical Society of India, Osmania University, Hy-derabad, February, 2007.

3. IUCAA-MPA workshop on Astrophysics, Inter-University Centre for As-tronomy and Astrophysics, Pune, March, 2007.


1. Visit to I.U.C.A.A., Pune, July 23 - 30, 2006 .

2. Visit to I.U.C.A.A., Pune, March 1 - 12, 2007.


1. Constraining accelerating universe, Lectures, Inter-University Centre for As-tronomy and Astrophysics Reference Centre Workshop, University of Delhi,India, October, 2006.

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Dileep Prabhakar Jatkar

Research Summary:

With J. R. David and A. Sen, I computed the spectrum of quarter BPS dyons infreely acting Z2 and Z3 orbifolds of type II string theory compactified on a sixdimensional torus. For large charges the result for statistical entropy computedfrom the degeneracy formula agrees with the corresponding black hole entropyto first non-leading order after taking into account corrections due to the curva-ture squared terms in the effective action. The result is significant since in thesetheories the entropy of a small black hole, computed using the curvature squaredcorrections to the effective action, fails to reproduce the statistical entropy associ-ated with elementary string states.

With J. R. David and A. Sen, I found the exact spectrum of a class of quarter BPSdyons in a generic N=4 supersymmetric ZN orbifold of type IIA string theory onK3× T 2 or T 6. We also find the asymptotic expansion of the statistical entropy tofirst non-leading order in inverse power of charges and show that it agrees withthe entropy of a black hole carrying same set of charges after taking into accountthe effect of the four derivative Gauss-Bonnet term in the effective action of thetheory.

With N. Banerjee and R. K. Jain, I studied interacting scalar field theory non-minimally coupled to gravity in the FRW background. We show that for a specificchoice of interaction terms, the energy-momentum tensor of the scalar field van-ishes, and as a result the scalar field does not gravitate. The naive space depen-dent solution to equations of motion gives rise to singular field profile. We care-fully analyze the energy-momentum tensor for such a solution and show that thesingularity of the solution gives a subtle contribution to the energy-momentumtensor. The space dependent solution therefore is not non-gravitating. Our con-clusion is applicable to other space-time dependent non-gravitating solutions aswell. We study hybrid inflation scenario in this model when purely time depen-dent non-gravitating field is coupled to another scalar field.

Publications:

1. J. R. David, D. P. Jatkar and A. Sen, Dyon Spectrum in N=4 SupersymmetricType II String Theories, JHEP 0611, 073, (2006)

2. J. R. David, D. P. Jatkar and A. Sen, Dyon Spectrum in Generic N=4 Supersym-metric ZN Orbifolds, JHEP 0701, 016, (2007)

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Preprints:

1. N. Banerjee, R. K. Jain and D. P. Jatkar, Non-Gravitating Scalar Field in theFRW Background,


1. Strings 2006, China, June 2006.

2. ISM06, India, December 2006.

3. From Strings to LHC, India, January 2007.

4. SERC THEP 2007, India, January 2007.


1. Dyon Spectrum in Generic N=4 SupersymmetricZN Orbifolds, ISM06, IOP, Bhubaneswar,Puri, December 2006.

2. Report on Brane-worlds working group, From Strings to LHC, TIFR, Goa, Jan-uary 2007.

3. Introduction to Anomalies, SERC THEP 2007, University of Hyderabad, Hy-derabad, January 2007.

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Pinaki Majumdar

Research Summary:

My work over the last one year has been mainly on the interplay of strong cou-pling, phase competition, and disorder in electron systems. The manganites re-main the focus, but the lessons learnt are of value in a wider class of materials.I have also worked on the problem of magnetism in the f electron metals, sug-gesting a framework for how the f metals evolve from standard weak couplingRKKY magnets to strong coupling ‘double exchange’ like systems. I have recentlystarted work on the double perovskites, and also a cluster DMFT study of heavyfermions.

Publications:

1. Sanjeev Kumar, Arno P. Kampf and Pinaki Majumdar, Domain Formation andOrbital Ordering Transition in a Doped Jahn-Teller Insulator, Phys. Rev. Lett.97, 176403, (2006)

2. Sanjeev Kumar, Arno P. Kampf and Pinaki Majumdar, The Effect of Disorderin an Orbitally Ordered Jahn-Teller Insulator, Phys. Rev. B 75, 014209, (2007)

Preprints:

1. Kalpataru Pradhan, Anamitra Mukherjee and Pinaki Majumdar, The Dis-tinct Effects of Homogeneous Weak Disorder and Dilute Strong Scatterers on PhaseCompetition in the Manganites, submitted for publication

2. Kalpataru Pradhan and Pinaki Majumdar, The Classical Kondo Lattice at In-termediate Coupling (in preparation)

3. Kalpataru Pradhan and Pinaki Majumdar, Magnetism Beyond the Ruderman-Kittel-Kasuya-Yosida Interaction: Revisiting the 4f Metals (in preparation)


1. Mesodis, IIT Kanpur, India, Dec 2006.

2. Correlated systems and novel materials, IIT Kharagpur, Jan 2007.

3. Indo-Japan meeting on magnetoresistive oxides, Tokyo, Feb 2007.

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1. Physical and Theoretical Chemistry Department, Oxford University, April-May 2006.

2. Institut Laue-Langevin, Grenoble, France, June-Aug 2006.

Other Activities:

1. Gave six lectures at a SERC School on ‘Magnetism and Superconductivity’at the University of Hyderabad in Nov 2006.

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100

Biswarup Mukhopadhyaya

Research Summary:

(a)Different aspects of supersymmetric (SUSY) theories have been studied, withspecial reference to collider signals at the Large Hadron Collider (LHC). One ofthe important outcomes of this investigations is the identification of novel signalsfor scenarios with a right sneutrino as the lightest supersymmetric particle, whichare being used by the experimentalists at the LHC.(Sudhir Kumar Gupta, Santosh Kumar Rai, Biswarup Mukhopadhyaya)(b)The implications of supersymmetric models in the neutrino have been inves-tigated. One area of study is the identification of viable regions in the SUSY pa-rameter space which correspond to the observed neutrino mass pattern and bi-large mixing, using flavour-dependent behaviour in the hidden sector of a brokenSUSY model.(R. Srikanth Hundi, Biswarup Mukhopadhyaya).Another aspect of the above study is the identification of SUSY models wherelepton number can be violated by two units (thereby allowing Majorana massesfor neutrinos) but violation by one unit is heavily suppressed (thereby ensuring aSUSY dark matter candidate). It was shown how a supergravity framework canlead to such a possibility.(R. Srikanth Hundi, Biswarup Mukhopadhyaya, Soumitra SenGupta).(c) It was shown that Little Higgs theories with broken T-parity can lead to sit-uations where the Higgs boson may have dominantly invisible decay modes. Itcould act as a distinctive signal of such theories in certain regions of the parame-ter space.(R. Srikanth Hundi, Biswarup Mukhopadhyaya, Andreas Nyffeler).(d) Implications of a degenerate neutrino scenario was studied, where the Majo-rana neutrino phases can lead to certain conclusions about the 1-3 mixing anglein the neutrino sector.(Rathin Adhikari, Anindya Datta, Biswarup Mukhopadhyaya).(e) Elaborate studies, including the writing of detailed simulation codes in thecontext of the LHC, are in progress, in the context of non-universal SUSY theories,and CP-violation in the SUSY sector.(Priyotosh Bandopadhyay, Subhaditya Bhattacharya, AseshKrishna Datta andBiswarup Mukhopadhyaya).

Publications:1. Sudhir Kumar Gupta, Biswarup Mukhopadhyaya, Santosh Kumar Rai, Right-

chiral sneutrinos and long-lived staus: Event characteristics at the large hadroncollider, Phys. Rev. D75, 075007 (2007).

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2. Raghavendra Srikanth Hundi, Biswarup Mukhopadhyaya, Andreas Nyf-feler Invisible Higgs boson decay in the Littlest Higgs model with T-parity, Phys.Lett B649, 280 (2007).

3. Biswarup Mukhopadhyaya, Raghavendra Srikanth, Bi-large neutrino mixingin R-parity violating supersymmetry: The Role of right-chiral neutrino superfields,Phys. Rev. D74, 075001 (2006).

4. Sudhir Kumar Gupta, Biswarup Mukhopadhyaya, Santosh Kumar Rai, Dis-tinguishing split supersymmetry in Higgs signals at the large hadron collider,Phys. Rev D73, 075006 (2006).

Preprints:

1. Rathin Adhikari, Anindya Datta, Biswarup Mukhopadhyaya, The neutrinomass scale and the mixing angle θ13 for quasi-degenerate Majorana neutrinos, hep-ph/0703318.

2. Biswarup Mukhopadhyaya, Soumitra SenGupta, Raghavendra Srikanth Hundi,Supergravity reconciles dark matter with lepton number violating neutrino masses,hep-ph/0609304.


1. Workshop on Physics at th LHC, TIFR, Mumbai, September, 2006.

2. International Workshop on Theoretical High Energy Physics, IIT, Rorkee, March,2007.


1. Indian Association for the Cultivation of Science, Kolkata, June-July, 2006.

2. University of Calcutta, Kolkata, January, 2007.


1. Some Implications of split supersymmetry, Indian Association for the Cultiva-tion of Science, Kolkata, July, 2006.

2. Extra dimensions and particle physics, Presidency College, Kolkata, July, 2006.

3. Why look beyond the standard model?, Workshop on Physics at the LHC, TataInstitute of Fundamental Research, Mumbai, September, 2006.

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4. Curled-up space in the laboratory, Kalyani University, West Bengal, September,2006.

5. New physics at the LHC, University of Calcutta, Kolkata, September, 2006.

6. Dogs that do not bark, International workshop on theoretical high energyphysics, IIT, Roorkee, Roorkee, March, 2007.


• Fellow, National Academy of Science, India, 2006.

Other Activities:

1. Member, Programme Advisory Committee, International Workshop on WeakInteraction and neutrinos (WIN07), Kolkata, January 2007.

2. Member, National Organising Committee, International workshop on theo-retical high energy physics, Roorkee, March, 2007.

3. Dean, academic, HRI, since August, 2006.

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Satchidananda Naik

Research Summary:Self-dual N = 8 Super gravity as open string

Here we take the super Lorentz groupOSp(8|2) as a local gauge group in theN =8 super space. The self-dual part of the field is formulated as a zero curvaturecondition in the twistor space. Due to twistors an off-shell formulation is possible.In the Frobenius gauge this can be formulated as a string theory. All the MHVgravity amplitudes are calculated.

Preprints:

1. The Open string formulation of N = 8 self-dual Super gravity to appearsoon


1. International String theory Workshop ,ISM06 at Puri, from Dec’12-22 06

Other Activities:Courses given: Mathematical Methods Part II from Jan-May 2007· · ·

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Andreas Nyffeler

Research Summary:

My field of research is phenomenological particle physics. I work on precisiontests of the Standard Model and on new physics models in the TeV region. Iam particularly interested in the analysis of the electroweak symmetry breakingsector in the Standard Model and its extensions and in the low-energy structureof the strong interactions.

I. Little Higgs models with T-parity at future collidersA few years ago, new physics models called Little Higgs, have been proposedas another solution to the hierarchy problem of the Standard Model. They aresituated somehow in between weakly interacting supersymmetric and stronglyinteracting Technicolor models. In addition to a light Higgs boson, many newparticles are predicted in the TeV region, which will be explored by the upcom-ing LHC collider and, later on, at an International Linear Collider (ILC). If someadditional discrete symmetry is invoked, called T-parity, there exists a lighteststable particle, usually the heavy neutral partner of the photon, which leads toevents with missing transverse energy and which can serve as a viable dark mat-ter candidate. A thorough understanding of the phenomenology of such LittleHiggs models with T-parity is necessary in order to distinguish them from theMSSM with R-parity or Universal Extra Dimensions (UED) with KK-parity. Withmy colleagues at HRI, I have started to work out some consequences for searchesfor these new particles in the Littlest Higgs model with T-parity (LHT) at the LHCand how to distinguish the signals from the MSSM and UED.

a) Invisible Higgs boson decay in the Littlest Higgs model with T-parity(with Raghavendra Srikanth Hundi and Biswarup Mukhopadhyaya)We have shown that there are regions in the parameter space of the LHT, allowedby electroweak precision data, where the Higgs boson can decay invisibly intoa pair of heavy photons AH with a substantial branching ratio. The BR(H →AHAH) varies between 93% and 5% for Higgs masses between 115 and 600 GeVand for a symmetry breaking scale f in the LHT in the range 450 - 550 GeV. Thetotal decay width of the Higgs boson in the LHT can thereby be enhanced by anorder of magnitude compared to the SM for Higgs masses around 130 GeV. It isvery likely that a Higgs boson with such a substantial invisible branching ratiocan be detected at the LHC and the ILC.

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b) Leptonic signals from the Littlest Higgs model with T-parity at the LHC(with Asesh Krishna Datta, Paramita Dey, Sudhir Kumar Gupta and BiswarupMukhopadhyaya)Very recently, we started some detailed simulations on specific signals in the LHTand the MSSM at the LHC (di- and trileptons, with or without hard jets and miss-ing energy) to explore regions in the parameter space, where these models differor where they might lead to similar event characteristics.

II. Anomalous magnetic moment of the muon

This is some ongoing long-term project with Marc Knecht and Michel Perrottet(CPT-CNRS, Marseille, France) on higher order hadronic corrections to the muong−2. Based on methods developed earlier for the evaluation of the pion-pole con-tribution to hadronic light-by-light scattering, we currently study the contribu-tions from scalar intermediate states. Using QCD short-distance constraints fromthe operator product expansion on the relevant form factors in large-NC QCD,in addition to experimental data on the form factors, and with a semi-analyticalapproach to the resulting two-loop integrals, we try to better assess the model de-pendence of earlier estimates in the literature. In this way we hope to get a bettercontrol of some of the hadronic uncertainties in the Standard Model predictionfor the muon g − 2 which presently make it difficult to interpret the deviationfrom the experimentally measured value.

Publications:1. R.S. Hundi, B. Mukhopadhyaya and A. Nyffeler, Invisible Higgs boson decay

in the littlest Higgs model with T-parity, Phys. Lett. B 649, 280, (2007)

Conference/Workshops Attended:1. Workshop on LHC Physics 2006, TIFR Mumbai, September 2006.

Talk: Little Higgs at the LHC

2. Topical Meeting on Physics at the LHC, HRI, December 2006.Talk: Effective Field Theories and the LHC

3. 21st International Workshop on Weak Interactions and Neutrinos (WIN07), SahaInstitute, Kolkata, January 2007.Talks: 1. Little Higgs models2. Invisibly decaying Higgs boson in the littlest Higgs model with T-parity

4. International Workshop on Theoretical High Energy Physics (IWTHEP07), IITRoorkee, March 2007.Talk: Invisibly decaying Higgs boson in the littlest Higgs model with T-parity

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Other Activities:

1. I was involved in the organization of a Topical Meeting on Physics at theLHC at HRI, December 2006.

2. I have organized at HRI, together with V. Ravindran, a discussion and read-ing group on Effective Field Theory and the Renormalization Group. I havealso given several lectures on effective field theories in this framework.February - May 2007.

3. Pheno lunch talk: Narrow width approximation limitations and Breakdownof the Narrow Width Approximation for New Physics (based on hep-ph/0703077and hep-ph/0703058), April 10, 2007.

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107

Sudhakar Panda

Research Summary:

We studied N = 4 gauged supergravity theory in four dimensions aiming at con-structing solutions that may provide a stringy explanation of cosmological prob-lems. We used contracted special orthogonal ( CSO ) groups for gauging to obtaina non-trivial scalar potential. This gauged theory did not admit stable de Sittersolution. However, we found solutions corresponding to the so-called cosmo-logical scaling solutions. These are interesting solutions which are expected toplay a role in explaining the accelerating expansion of the universe. During thisstudy we also established the conditions and proved a mathematical lemma onthe existence ofinvariant metrics on CSO-algebras of rank twelve.

The effective action for gravitational interaction resulting from string theory con-tains, besides the usual two derivative terms, many higher derivative terms. Theentropy of the black holes in this theory, thus, gets contributions from thesehigher derivative terms as well. A class of these black holes are found to havethe same entropy as expected from supersymmetric black holes. This observa-tion requires that the effective action itself should be supersymmetric. Since theeffective actions are constructed in a way which does not guarantee manifest su-persymmetry, one has to explicitly construct supersymmetric actions involvingthe higher derivative terms. We have made a lot of progress in this direction forHeterotic string theory and we expect to complete the project soon.

Publications:

1. M.de Roo, D.B. Westra and Sudhakar Panda, Gauging CSO groups in N = 4supergravity, JHEP 09, 011, (2006)

2. Sudhakar Panda, Vacua in N = 4 gauged supergravity, Mathematical PhysicsProc. 12th regional conf. Islamabad, 190, (2006)

Preprints:

1. M.de Roo, D.B. Westra and Sudhakar Panda, Gauging CSO groups in N = 4supergravity, hep-th/0606282

2. Sudhakar Panda, Vacua in N = 4 gauged supergravity, HRI-P-06-08-004


1. ISM-06 (Indian String meeting, Puri), India , December 2006,

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2. FTAG-V (Field theoretic aspects of gravity, Goa, India, December 2006,

3. From Strings to LHC, Goa, India, January 2007.


1. Centre for Theoretical Physics, Univ. of Groningen, Groningen, The Nether-lands, September 2006,

2. TIFR, Mumbai, India, December 2006.


1. Fundamental particles in Nature and how they are held together (six lectures forschool students), JBNSTS lectures, Aizwal, Mizoram, August 2006.

2. What is Supersymmetry (two lectures), for B.Sc. students, G.C. Govt. college,Silchar, Assam, August 2006.

3. Supersymmetry: a problem or solution?, Colloquium, Univ.of Jamia-Millia Is-lamia, Delhi, August 2006.

4. Constructing supergravity theory with higher derivative terms, Invited talk inFTAG-V, Goa, December 2006.

5. Brief review of String Cosmology, Workshop, From Strings to LHC, Goa, Jan-uary 2007.

Other Activities:

1. Dean Administration, April-July, 2006.

2. Convener, Security Committee, 2006-07.

3. Member,Local Works Committee, 2006-07

4. Invited Member, Academic selection committee meeting, April 2006.

5. Participating member, Meeting of Registrars with JS (R&D), DAE, June 2006.

6. External Member, Ph.D defence board, Groningen university, September2006.

7. Expert member, faculty selection board of Jamia Univ, November 2006.

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8. Represented HRI in DAE meeting on panel discussion on suggestions for6th Pay-commission, March 2007.

9. Taught a course on Quantum Field Theory under HRI Ph.D. course pro-gram, January-May 2007.

10. Supervised two students under the summer visiting students program ofHRI, May, June and July 2007.

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110

Tribuvan Prasad Pareek

Research Summary:

We have continued studying spin transport in nanosystems. In particular westudied spin-orbit induced torque and its relation on magnetization reversal andquantum computation. A theoretical frame work of spin density scattering ma-trix developed by us has been used towards this end. We have shown that spin-orbit (SO) interaction can induce a torque for the collinear configuration of spinvalve structure (F1/2DEG/F2). Further, it is argued that this SO-induced torquecan induce magnetization reversal even in collinear spin valves. The theoreticalestimates of this effect that are made are well within the reach of present dayexperimental observations. In addition, it is shown that the same mechanism al-lows one to increase the purity of the outgoing current and produces entangledspin states essential for quantum computation. A scattering theory for the spin-density matrix is developed. Using this theory, the SO-induced torque and theassociated von Neumann entropy are studied quantitatively.

Generation and detection of spin currents in non-magnetic systems in absenceof magnetic field has also been studied. This is an important problem and ouranalysis shows that in two terminal systems one can generate and detect spincurrents via conductance measurement.

Publications:

1. T. P. Pareek, Spin-orbit-induced torque in a collinear spin valve: A possible routeto design fast magnetic memory, PRB 75, 115308, (2007)

2. T. P. Pareek, . Measuring Spin Hall conductance and Rashba spin orbit interactionvia electrical measurement in Y shape conductor. , To appear in IJMPB volume-number, page number, (2007)

Preprints:

1. T. P. Pareek and A. M. Jayannavar, Generation and Measurement of Non Equi-librium Spin Currents in Two Terminal Systems, eprint number,if any

2. Authors and co-authors name, Title of the paper, write (in preparation) if itdoes not have any preprint number

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1. National Conference on Recent Advances in Material Science, ,,Kurukshetra Uni-versity India, September 27-29, 2006

2. Physics of Mesoscopic and Disordered Materials (MESODIS - 06) , I.I.T KanpurIndia, December 2006.

3. K. S. Krishnan Discussion Meeting on Frontiers In Quantum Science , IMSCChennai India, December 2006.


1. Institute of Physics, Bhubaneswar, India, April, 2007


1. Materials for Spintronics: Diluted Magnetic Semiconductor, , National Confer-ence on Recent Advances in Material Science, Kurukshetra University ,Kurukshetra , September 2006.

2. Transport Spin Currents and Its Measurement , International Workshop on Physicsof Mesoscopic and Disordered Materials (MESODIS - 06), I. I. T, Kanpur,Kanpur, December 2006.

3. Spintronics: From two dimensional electrons gas to Carbon naontubes. , K. S. Kr-ishnan Discussion Meeting on Frontiers In Quantum Science , IMSC, Chen-nai, Chennai, December 2006.

Other Activities:

1. I have taught a full semester course on condensed matter physics from Aug2006 - Dec. 2006

2. 7 visiting students have worked with me during the academic year.

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112

Mina Ketan Parida

Research Summary:

Major areas of research during 2006-2007:-

1. High scale mixing unification.

2. Fermion masses and family unification.

3. Supersymmetric SO(10) grand unification.

4. Baryogenesis through leptogenesis under the gravitino constraint.

Publications:

1. Adhikary, Biswajit, Brahmachari, Biswajoy, Ghosal, Ambar, Ma, Ernest &Parida, M. K. A4 symmetry and prediction of Ue3 in a modified Altarelli-Ferugliomodel, Phys. Lett. B 638, 345 (2006).

2. Agarwalla, Sanjib Kumar, Parida, M. K., Mohapatra, R. N. & Rajasekaran,G. Neutrino mixings and leptonic CP-violation from CKM matrix and Majoranaphases, Phys. Rev. D 75 , 033007 (2007).

3. Majee, Swarup Kumar, Parida, Mina K. , Raychaudhuri Amitava & SarkarUtpal, Low intermediate scales for leptogenesis in supersymmetric SO(10) grandunified theory, Phys. Rev. D 75, 075003 (2007).

4. Parida, M. K. & Sinha, N. Working group report: Flavor physics and model build-ing, Pramana 67, 849 (2006).


1. Institute of Mathematical Sciences, Chennai, December 2006.

Other Activities:

1. A4 symmetry and large neutrino mixings, HRI pheno-lunch talk in high energyphysics, Nov. 2006.

2. High scale mixing unification, Talk presented at HRI Annual symposium,March, 2007.

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Sumathi Rao

Research Summary:

We continued our investigations of junctions of quantum wire. This year westudied the effect of a Kondo spin at the junction of three or more wires. We alsostudied the patterns of time- dependent transport through a dot at the junction ofquantum wires.

We are currently studying the problem of how the current through a mesoscopicconductor can be dephased by leakage of current through other wires attached tothe junction.

We are also studying transport through a normal-superconductor-normal junc-tion and in particular, we are studying the effect of electron-electron interactionson the Andreev reflection.

Finally, we have started working on graphene and in particular, the role of defectsin graphene.

Publications:

1. Sourin Das, Sumathi Rao and Diptiman Sen, Effects of interactions and junc-tions on conductances of quantum wires, in Special Issue on the International Con-ference on Nanoscience and Technology, eds. M. K. Sanyal, A. K. Raychaudhuriand D. Chakravorty, International Journal of Nanoscience 4 951 - 956, (2005).

2. Ravi Chandra, Sumathi Rao and Diptiman Sen, A multi-channel fixed pointfor a Kondo spin coupled to a junction of Luttinger liquids, Europhys. Lett. 75,797, (2006)

3. Ravi Chandra, Sumathi Rao and Diptiman Sen , Renormalisation group studyof the Kondo problem at a junction of several quantum wires Phys. Rev. B75,045435 (2007)

4. Shamik Banerjee, Anamitra Mukherji, Sumathi Rao and Arijit Saha Adiabaticcharge pumping through a dot at the junction of N quantum wires Phys. Rev.B75, 153407 (2007)

Preprints:

1. Anamitra Mukherji, Sumathi Rao and Arijit Saha, Transport through a quan-tum dot pump at a multiple wire junction, (in preparation)

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1. Physics near the Mott transition, Bangalore, India, 20-25 July 2006

2. Conference-cum-seminar on Emerging trends in physics, S.G.T.B Khalsa college,New Delhi, India, Sept 20-23, 2006.

3. National Conference on Convergence with physics, Jamshedpur, India, 10-11 Oc-tober, 2006

4. K S Krishnan Discussion Meeting on Frontiers in Quantum Science, Chennai,India, 13-14 December 2006

5. Workshop on correlated systems and novel materials, Kharagpur, India, Jan 16-18, 2007

6. SERC Theoretical High Energy School, Hyderabad, Jan 19-27, 2007.


1. Indian Institute of Science, Bangalore, India, July, 2006

2. Indian Institute of Technology, Kanpur, September 2006


1. Adiabatic charge pumping through dots and junctions, Indian Institute of Sci-ence, Bangalore, July 17, 2006.

2. Correlated electron transport through junctions of quantum wires, Indian Insti-tute of Technology, Kanpur, Sept 19, 2006.

3. Novel phenomena in low dimensional physics. Indian Institute of Technology,Kanpur, Sept 20, 2006.

4. Science: A journey into new frontiers, Convergence with Physics, JamshedpurWomen’s college, Jamshedpur, October 2006.

5. Women in Physics in India Panel discussion on Nurturing women in physics,Convergence with Physics, Jamshedpur Women’s college, Jamshedpur, Oc-tober 2006.

6. Novel phenomena in low dimensional physics , Workshop on correlated systemsand novel materials, Indian Institute of Technology, Kharagpur, Jan 2007.

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7. Tutored course on Anomalies, SERC Theoretical High Energy School, Hyder-abad, Jan 19-27, 2007.

8. High energy physics at low energies, HRI local symposium, March 20, 2007.

Other Activities:

1. Taught advanced quantum mechanics , Jan-May 2007

2. Convenor, Local works committee

3. Convenor, Women’s grievance cell

4. Member, Faculty Advisory committee and Budget committee

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116

V. Ravindran

Research Summary:

The fixed order QCD predictions often have limitations in applicability due tothe presence of various logarithms that become large in some kinematic regionswhich otherwise can be probed by the experiments. The standard approach toprobe these regions is to resum the class of such large logarithms supplementedwith fixed order results. This can almost cover the dominant kinematic regionof the phase space. Recently, we have extracted soft distribution functions forDrell-Yan and Higgs production processes using mass factorisation theorem andthe perturbative results that are known upto three loop level and are found tobe maximally non-abelian. We have shown that these functions satisfy Sudakovdifferential equations. The formal solutions to such equations and also to themass factorisation kernel upto four loop level are presented. We have obtainedthe threshold resummation exponents upto three loop using the soft distribu-tion function which are important to study the effects of resummation. We havealso predicted threshold enhanced QCD corrections to inclusive processes suchas Deep inelastic scattering, Drell-Yan process and Higgs productions throughgluon fusion and bottom quark annihilation processes using the resummed crosssections. Generalising our approach, we have demonstrated a similar resumma-tion of soft gluons can be done for the energy distribution of bottom quarks inthe Higgs decay as well as for the hadroproduction in l+l− annihilation processesand differential distributions of DY pairs and Higgs. We have shown that thesehigher order threshold QCD corrections improve the theoretical predictions forthe Higgs Boson production through gluon fusion at hadron colliders which isone of the discovery mode of the most wanted particles in high energy physics.

Publications:

1. J. Blumlein and V. Ravindran. O(α2s) timelike Wilson coefficients for parton-

fragmentation functions in Mellin space, Nucl.Phys.B749:1-24(2006), arXiv:hep-ph/0604019

2. M. C. Kumar, P. Mathews and V. Ravindran. PDF and scale uncertainties ofvarious DY distributions in ADD and RS models at hadron colliders, Eur.Phys.J.C49:599-611(2007), arXiv:hep-ph/0604135,

3. J. Blumlein and V. Ravindran. QCD threshold corrections to Higgs decay and tohadroproduction in l+l− annihilation, Phys.Lett.B640:40-47(2006), arXiv:hep-ph/0605011,

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4. V. Ravindran, J. Smith and W. L. van Neerven, QCD threshold corrections todi-lepton and Higgs rapidity distributions beyond N 2LO, Nucl. Phys. B767,100-129(2007), arXiv:hep-ph/0608308


1. Workshop on LHC Physics, TIFR, Mumbai,India,September 2-8,2006


1. Lorentz Institute, University of Leiden, Leiden, The Netherlands, June 1stto August 30th 2006,

2. Nikhef, Amsterdam, The Netherlands, August 2006.

3. LPTHE,Paris, July 27,28, 2006.

4. KEK, Tsukaba, Japan, November 1st to December 31st 2006

5. Wako,RIKEN, Tokyo, Japan, December 13-14,2006

6. Kyoto University, Japan, December 20-22, 2006


1. Sudakov resummation and Threshold corrections to inclusive processes in QCD ,Department Seminar, LPTHE , Paris, July 2006.

2. Sudakov Resummation for Higgs production , Institute Seminar, Nikhef , Ams-terdam, August 2006.

3. Two lectures on Perturbative Quantum Chromodynamics,Workshop Talk,TIFR,Mumbai, September 2006.

Other Activities:

1. Taught a course on ”Perturbative QCD” in SERC school held in Universityof Hyderabad, January, 2007.

2. Taught a semester course on ”Atomic, Molecular and Nuclear Physics” atHRI, 2007.

3. Guided a summer student.

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Amitava Raychaudhuri

Research Summary:

In 2006-07, research has been carried out in aspects of neutrino physics, modelsbased on space-time with extra dimensions, and grand unified theories. Theseare briefly discussed in turn below.

In neutrino physics, a considerable effort has been spent on the prospects of abeta-beam facility – a source of pure νe or νe beams. It has been shown that sucha facility has unique advantages in both long- and short-baseline set-ups to bet-ter determine and constrain neutrino mass and mixing parameters as well as toexplore non-Standard physics, like R-parity violating supersymmetry.

Research has also been carried out to determine how well the ICAL detector atINO will be able to probe the neutrino mass splitting and mixing angle relevantfor atmospheric neutrino oscillations.

Models in which space-time has more than four dimensions have been examinedfor the unification of gauge couplings at high energies.

A light intermediate scale in GUTS is a necessary ingredient for satisfying the re-quirement of proper leptogenesis. Obtaining such an intermediate scale is fraughtwith difficulties. It has been shown that within SUSY SO(10) GUTs this may bepossible if the Higgs multiplets are appropriately chosen (16 rather than 126) andthreshold corrections are incorporated. Alternate possibilities include the use ofnon-renormalisable Planck scale interactions and/or introduction of additionalchiral multiplets.

Publications:1. Rathin Adhikari, Sanjib Kumar Agarwalla, and Amitava Raychaudhuri,

Can R-parity violating supersymmetry be seen in long baseline beta-beam experi-ments?, Phys. Lett. B642, 111–118 (2006)

2. Gautam Bhattacharyya, Anindya Datta, Swarup Kumar Majee, and Ami-tava Raychaudhuri, Power law running in Universal Extra Dimension scenar-ios, Nucl. Phys. B760, 117-127 (2007)

3. Swarup Kumar Majee, Mina K. Parida, Amitava Raychaudhuri and UtpalSarkar, Low intermediate scales for leptogenesis in SUSY SO(10) GUTs, Phys.Rev. D75, 075003 (2007)

4. Sanjib Kumar Agarwalla, Subhendu Rakshit, and Amitava Raychaudhuri,Probing Lepton Number Violating Interactions with Beta-beams, Phys. Lett. B647,380-388 (2007)

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5. Sanjib Kumar Agarwalla, Sandhya Choubey, and Amitava Raychaudhuri,Neutrino mass hierarchy and θ13 with a magic baseline beta-beam experiment,Nucl. Phys. B771, 1-27, 2007

Preprints:

1. Sanjib Kumar Agarwalla, Sandhya Choubey, Srubabati Goswami, and Ami-tava Raychaudhuri, Neutrino parameters from matter effects in Pee at long base-lines, hep-ph/0611233, Phys. Rev. D (to appear)

2. Abhijit Samanta, Sudeb Bhattacharya, Ambar Ghosal, Kamales Kar, Deba-sish Majumdar, and Amitava Raychaudhuri, A GEANT-based study of atmo-spheric neutrino oscillation parameters at INO, hep-ph/0702180

3. M. Sajjad Athar et al., India-based Neutrino Observatory: Project Report. VolumeI, INO-2006-01


1. Workshop on LHC Physics, TIFR, India, September, 2006.

2. Topical Meeting on Physics at the LHC, HRI, India, December, 2006.

3. JIGSAW 2006, TIFR, India, February, 2007,


1. Neutrino mass hierarchy and θ13 with a magic baseline beta-beam experiment, JIG-SAW - the Joint Indo-German School and Workshop, TIFR, Mumbai, Febru-ary 2007.

2. Neutrino Novelties, Department of Physics, Presidency College, Kolkata, De-cember 2006.

3. Neutrino physics today, One-day meeting on the India-based Neutrino Ob-servatory, Department of Physics, University of Calcutta, November 2006.

4. Neutrino mass hierarchy and θ13 with a magic baseline beta-beam experiment,Homi Bhabha Lecture, University of Durham, November 2006.

5. The India-based Neutrino Observatory: Status and Physics Prospects, Homi BhabhaLecture, University of Liverpool, November 2006.

6. Neutrino mass hierarchy and θ13 with a magic baseline beta-beam experiment,Homi Bhabha Colloquium, Cockcroft Institute, Warrington, November 2006.

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7. The India-based Neutrino Observatory: Status and Physics Prospects, Homi BhabhaColloquium, University of Glasgow, November 2006.

8. Neutrino mass hierarchy and θ13 with a magic baseline beta-beam experiment,Homi Bhabha Lecture, University of Southampton, November 2006.

9. The India-based Neutrino Observatory: Status and Physics Prospects, Homi BhabhaColloquium, Imperial College, London, November 2006.

10. The India-based Neutrino Observatory: Status and Physics Prospects, Homi BhabhaLecture, University of Oxford, November 2006.

11. The India-based Neutrino Observatory: Status and Physics Prospects, NationalConference on the Emerging Trends in Physics, SGTB Khalsa College, NewDelhi, September 2006.

12. Electroweak Symmetry Breaking, Workshop on LHC Physics, TIFR, Mumbai,September 2006.

13. Neutrinos Today, Colloquium, Inter-University Centre for Astronomy andAstrophysics, Pune, April 2006.

14. Neutrinos Today, INO Training School, HRI, Allahabad, April 2006.


• Homi Bhabha Lecturership, Institute of Physics (UK) and the Indian PhysicsAssociation, 2006.

Other Activities:

1. Member, Governing Board, IUCAA, Pune.

2. Visitors’s Nominee, Academic Council, Visva-Bharati, Santiniketan.

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121

Ashoke Sen

Research Summary:

My research during the period April 2006 - March 2007 focussed on the study ofblack holes in string theory and gaining a precise understanding of the relation-ship between black hole entropy and statistical entropy obtained by taking thelogarithm of the degeneracy of quantum states. In order to push this program toits logical end one needs to open two fronts: 1) developing tools for computingblack hole entropy to greater accuracy and 2) computing degeneracy of quantumstates in string theory to greater accuracy. Progress was made on both fronts invarious collaborations. For the computation of black hole entropy we pushed theentropy function approach (which was developed during the previous year) tostudy entropy of various black holes in string theory in the presence of higherderivative terms. We also showed how the entropy function approach can begeneralized to rotating black holes and how it can be used to derive general prop-erties of entropy of non-supersymmetric black holes. For the computation of thestatistical entropy we found exact expressions for the degeneracies of supersym-metric states in a class of N=4 supersymmetric string theories, and showed howthe result agrees with the black hole entropy even after including the effect ofhigher derivative terms.I also worked on the subject of open string tachyon condensation and showedthat under certain circumstances the conventional open string tachyon can begiven a geometric interpretation.

Publications:1. J. R. David and A. Sen, “CHL dyons and statistical entropy function from

D1-D5 system,” JHEP 0611, 072 (2006) [arXiv:hep-th/0605210].

2. D. Astefanesei, K. Goldstein, R. P. Jena, A. Sen and S. P. Trivedi, “Rotatingattractors,” JHEP 0610, 058 (2006) [arXiv:hep-th/0606244].

3. J. R. David, D. P. Jatkar and A. Sen, “Dyon spectrum in N = 4 supersymmet-ric type II string theories,” JHEP 0611, 073 (2006) [arXiv:hep-th/0607155].

4. B. Sahoo and A. Sen, “alpha’-Corrections to Extremal Dyonic Black Holesin Heterotic String Theory,” JHEP 0701, 010 (2007) [arXiv:hep-th/0608182].

5. J. R. David, D. P. Jatkar and A. Sen, “Dyon spectrum in generic N = 4 super-symmetric Z(N) orbifolds,” JHEP 0701, 016 (2007) [arXiv:hep-th/0609109].

6. A. Dabholkar, A. Sen and S. P. Trivedi, “Black hole microstates and attractorwithout supersymmetry,” JHEP 0701, 096 (2007) [arXiv:hep-th/0611143].

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7. A. Dabholkar, N. Iizuka, A. Iqubal, A. Sen and M. Shigemori, “Spinningstrings as small black rings,” JHEP 0704, 017 (2007) [arXiv:hep-th/0611166].

8. A. Sen, “Walls of Marginal Stability and Dyon Spectrum in N=4 Supersym-metric String Theories,” 0705, 039 (2007) [arXiv:hep-th/0702141].

9. A. Sen, “Geometric tachyon to universal open string tachyon,” JHEP 0705,035 (2007) [arXiv:hep-th/0703157].


1. IPM String School & Workshop , Iran, April 2006

2. Strings 2006, China, June 2006.

3. IOP String School, Bhubaneswar, India, September 2006.

4. First Asian Winter school on String Theory, Seoul, Korea, January 2007


1. Stanford University, Stanford, USA, May 2006 (as SITP distinguished lec-turer)

2. University of Chicago, Chicago, May 2006

3. Raman Research Institute, Bangalore, July 2006

4. Indian Institute of Science, Bangalore, August 2006

5. University of Rome, Rome, November 2006

6. Caltech, Pasadena, USA, February - March 2007 (as Moore distinguishedscholar)

Invited Lectures/Seminars at Schools/Conferences:

1. Entropy Function and Dyons Partition Function in CHL Models, IPM StringSchool lecture, IPM, Tehran, Iran, April 2006.

2. New results from black hole entropy function, Strings 2006 conference talk, Bei-jing, China, June 2006.

3. Extremal Black Holes in String Theory, IOP String School lectures, IOP, Bhubaneswar,India, September 2006.

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4. Extremal Black Holes in String Theory First Asian Winter school on String The-ory lectures, KIAS, Seoul, Korea, January 2007.


• Pius XI Gold Medal, Pontifical Academy of Sciences, 2006

• J C Bose Fellowship, DST, 2006

Other Activities:

1. Taught Statistical Mechanics, January - May 2006.

2. Taught Quantum Field Theory 2, August - December 2006.

3. Taught Flux Compactification, January - May, 2007.

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Prasenjit Sen

Research Summary:

My main research activity during this period has been to understand structural,electronic and magnetic properties of small bi-metallic clusters. The particularsystem we have focussed on is 3d transition metal (TM) doped sodium clusters.Recently it has been claimed that small TM doped Au clusters have large mag-netic moments. On general chemical arguments we predicted that TM dopedsmall alkali metal clusters of same size will have larger magnetic moments. Thisled us to do detailed first-principles electronic structure calculation of these clus-ters. Our calculations show that indeed these clusters have large moments. Whatis surprising is that early TM (Sc, Ti and V) doped Na5 and Na6 clusters have mo-ments that are larger than the moments on the corresponding isolated TM atoms.It turns out that a large overlap of TM d and Na s states lead to larger occupancyof d-type states compared to isolated TM atoms in the early TM series. This leadsto an enhancement of the moment on the TM atoms in these clusters. It is inter-esting to note that there is no such s-d overlap in TM-Au6 clusters, and hence thecorresponding moments are also smaller.

A second problem that I have worked on in collaboration with Prof. G. P. Dasof the IACS, Kolkata and his group is to search for Si-based nano-cluster systemssuitable for hydrogen storage. In the process we have discovered through first-principles calculations that a Si60H60 cluster forms a (meta)-stable, highly sym-metric fullerene structure. This is very surprising in view of the well-known factthat pure Si60 does not form fullerene structure, unlike C60. We are now study-ing hydrogen storage on Ti atoms attached to the pentagonal faces of the Si60H60

fullerenes.

Another problem I have worked on is to study magnetic properties on alkalimetal dioxide solids, in collaboration with Dr. Priya Mahadevan of the SNBNCBS,Kolkata. First-principles calculations based density functional theory (DFT) withinlocal spin-density approximation (LSDA) predict that solid KO2 has a ferromag-netic ground state. This is surprising in view of that fact that there are no elementswith unfilled d or f shells in this compound. In order to be convinced that resultnot an artifact of LSDA (though LSDA, in general, reduce spin polarization), wedid ab initio quantum Monte Carlo (QMC) calculations for the electronic structureof this solid. QMC methods work with correlated wavefunctions, and usually re-produce/predict properties of materials much more accurately. To our surprise,QMC calculations also predict KO2 solid to have a ferromagnetic ground state.We are now in the process of understanding the microscopic origin of this un-usual ferromagnetism.

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Publications:

1. Prasenjit Sen, Peierls instability and electron-phonon coupling in a one-dimensionalsodium wire, Chemical Physics Letters 428, 430, (2006)

Preprints:

1. Kalpataru Pradhan and Prasenjit Sen, Unexpectedly large moments on TM@Nanclusters: (TM=Sc, Ti, V; n = 5, 6),


1. Workshop on Computational Materials Theory, India, July, 2006.

2. Materials Modeling at Different Length Scales, India, October 2006.


1. Indian Association for the Cultivation of Science, Kolkata, India, April 2006.

2. IACS, Kolkata, India, December 2006.

3. S. N. Bose National Center for Basic Sciences, Kolkata, India, March 2007.


1. Peierls instability and electron-phonon coupling in a one-dimensional sodium wire,Materials Modeling at Different Length Scales, DAE-BRNS, BARC, Mumbai,October 2006.

Other Activities:

1. I have been acting as the contact person for HRI in the National Grid Initia-tive (Garuda).

2. I organized a set of lectures for the VSP students in condensed matter physicsduring the summer of 2006. I was also one of the speakers. I advised twostudents – Kinjal Das Biswas (IITK) and Varada Bal (IIT-Kgp) for their VSPprojects.

3. I taught a course on Numerical Methods during the Aug-Dec semester,2006.

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L. Sriramkumar

Research Summary:

During the last year, my research work was primarily focused on investigatingthe following problems in inflationary cosmology:

1. Planck scale corrections to the primordial spectrum

2. Amplification of tachyonic perturbations at super-Hubble scales

3. Generation of features in the primordial spectrum

4. Evolution of perturbations in bouncing universes

and the following issues in black hole physics:

1. Domain of validity of semiclassical gravity around black holes

2. Entropy of black hole and cosmological horizons in brane-world scenarios

I have been studying the issues 2-4 listed above under inflationary cosmologyalong with my graduate student Rajeev Kumar Jain. Brief description of oneof the problems we have been investigating in this context can be found in hisreport. In what follows, I shall briefly describe the work I have been involved inunderstanding the domain of validity of semiclassical gravity around black holes.

Semiclassical gravity refers to the theory wherein a quantum matter field evolvesin a classical gravitational background, and the backreaction of the quantum fieldon the gravitational background is assumed to be given by the expectation valueof the stress-energy tensor of the quantum field. Such a semiclassical theory isexpected to break down when the fluctuations in the backreaction term—viz.the stress-tensor of the matter field—turns out to be ‘large’. With such a mo-tivation in mind, we are presently involved in evaluating the noise kernel ofthe stress-energy tensor of a quantized, conformally coupled and massless scalarfield around the (2 + 1)-dimensional Banados-Teitelboim-Zanelli black hole. Inparticular, we are interested in understanding the dependence of the amplitudeof the fluctuations in the stress-energy tensor on the distance from the black hole.

Publications:

1. L. Sriramkumar and S. Shankaranarayanan, Path integral duality and Planckscale corrections to the primordial spectrum in exponential inflation, JHEP 0612,050 (2006).

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Preprints:

1. H. K. Jassal and L. Sriramkumar, Entropy of BTZ black strings using the brickwall approach, gr-qc/0611102.

2. R. K. Jain, P. Chingangbam and L. Sriramkumar, Amplification of tachyonicperturbations at super-Hubble scales, astro-ph/0703762.


1. Inflation+25: The First 25 Years of Inflationary Cosmology, Institut d’Astro-physique,Paris, France, June 26–30, 2006.

2. Field Theoretic Aspects of Gravity V, Birla Institute of Technology and Science,Goa, December 18–23, 2006.

3. XXIV Meeting of the Indian Association of General Relativity and Gravitation,Jamia Millia Islamia, New Delhi, February 5-8, 2007.


1. High Energy, Cosmology and Astroparticle Physics Section, The Abdus SalamInternational Centre for Theoretical Physics, Trieste, Italy, July 4–18, 2006.

2. Institute of Physics, Bhubaneswar, August 21–24, 2006 and January 14–17,2007.

3. Inter-University Centre for Astronomy and Astrophysics, Pune, December24, 2006–January 1, 2007.


1. An introduction to inflation and cosmological perturbation theory, Seminar atInstitute of Physics, Bhubaneswar, August 23, 2006.

2. Inflation—A window to Planck scale physics, Seminar at Institute of Physics,Bhubaneswar, August 23, 2006; Invited talk in Field Theoretic Aspects ofGravity V Birla Institute of Technology and Science, Goa, December 18–23,2006.

3. The current status of inflationary cosmology, Colloquium at Institute of Physics,Bhubaneswar, January 15, 2007.

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Other Activities:

1. I was the chair for the workshop on Quantum Gravity at the XXIV Meet-ing of the Indian Association of General Relativity and Gravitation held at JamiaMillia Islamia, New Delhi during February 5-8, 2007.

2. Taught a full-semester course on Astrophysics to physics graduate studentsat HRI during August–December, 2006.

3. Taught a half-semester course on Cosmology to physics graduate studentsat HRI during January–March, 2007.

4. Guided the following two HRI graduate students on projects:• Anindya Dey, January–May 2007, Topic: Evolution of perturbations inbouncing universes.• Girish P. Kulkarni, January–May 2007, Topic: Generation of perturbationsin the inflationary scenario.

5. Guided the following student on a project under the Visiting Students’ Pro-gram: Arindam Chatterjee, B.Sc. Physics, III year, Chennai MathematicalInstitute, Chennai, India, May–June 2006. Topic: Dark energy.

6. I was incharge of conducting (the Physics part of) the HRI Science TalentTest 2006.

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129

Sanjib Kumar Agarwalla

Research Summary:

My work is mainly focused on the precision measurements of the neutrino os-cillation parameters mainly the issue of neutrino mass ordering and θ13 in theplanned/proposed next generation long baseline neutrino experiments like BetaBeam, Neutrino factory. In this context, we have studied the prospects of a BetaBeam source at CERN and ICAL at INO as the far detector. The CERN-INO dis-tance is close to the so-called “magic” baseline which helps to remove some ofthe parameter degeneracies and allows for a better measurement of the neutrinomass hierarchy and θ13.

We have explored the possibility of seeing the clear signal of new-physics in r-parity violating supersymmetric scenario with Beta Beam in a near and a far de-tector.

I have done some renormalization group evolution analysis (RGE) in the light ofthe high scale mixing unification hypothesis with the help of Prof. M. K. Parida.

I am a member of India-Based Neutrino Observatory (INO) Collaboration and Ihave done some simulation study with Nuance and Geant.

Publications:1. Rathin Adhikari, Sanjib Kumar Agarwalla, Amitava Raychaudhuri, Can R-

parity violating supersymmetry be seen in long baseline beta-beam experiments?,Phys.Lett.B 642, 111-118, (2006)

2. Sanjib Kumar Agarwalla, Subhendu Rakshit, Amitava Raychaudhuri, Prob-ing Lepton Number Violating Interactions with Beta-beams., Phys.Lett.B 647,380-388, (2007)

3. Sanjib Kumar Agarwalla, Sandhya Choubey, Amitava Raychaudhuri, Neu-trino mass hierarchy and θ13 with a magic baseline beta-beam experiment., NuclearPhysics B 771, 1-27, (2007)

4. S.K. Agarwalla, M.K. Parida, R.N. Mohapatra, G. Rajasekaran, NeutrinoMixings and Leptonic CP Violation from CKM Matrix and Majorana Phases.,Phys.Rev.D 75, 033007, (2007)

Preprints:1. Sanjib Kumar Agarwalla, Sandhya Choubey, Srubabati Goswami, Amitava

Raychaudhuri, Neutrino parameters from matter effects in the νe survival proba-bility at long baselines., hep-ph/0611233

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1. 2nd phase of INO SCHOOL, VECC/SINP, Kolkata, India, May 1-13, 2006.

2. 17th DAE-BRNS Symposium on HEP, IIT KHARAGPUR, India, Dec, 2006.

3. 21st International Workshop on Weak Interactions and Neutrinos (WIN07), SINP,Kolkata, India, Jan, 2007.

4. Joint Indo - German School and Workshop 2007 (JIGSAW ’07), TIFR, Mumbai,India, February, 2007.

5. INO Collaboration meeting, University of Delhi, Delhi, India, 9th March, 2007.

6. International Workshop on Theoretical High Energy Physics (IWTHEP), IIT, Roor-kee, India, March, 2007.


1. Physical Research Laboratory, Ahmedabad, India, January, 2007.

2. Centre for Theoretical Physics, Jamia Millia Islamia, New Delhi, India, March,2007.


1. Physics reach of CERN-INO baseline with beta beams, Poster presented at Neu-trino 2006, Santa Fe, USA, June, 2006.

2. Neutrino mass hierarchy and θ13 with a magic baseline Beta Beam experiment,17th DAE-BRNS Symposium on HEP, IIT, KHARAGPUR, India, December,2006.

3. Neutrino mass hierarchy and θ13 with a magic baseline Beta Beam experiment,Theoretical Physics Seminar Circuit talk, Physical Research Laboratory, Ahmed-abad, India, January, 2007.

4. Neutrino mass hierarchy and θ13 with a magic baseline Beta Beam experiment,WIN07, SINP, Kolkata, India, January, 2007.

5. Neutrino mixings and leptonic CP violation from CKM matrix and Majoranaphases, WIN07, SINP, Kolkata, India, January, 2007.

6. New physics search at INO, Poster presented at Joint Indo - German Schooland Workshop 2007 (JIGSAW ’07), TIFR, Mumbai, India, February, 2007.

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7. Neutrino mixings and leptonic CP violation from CKM matrix and Majoranaphases, Joint Indo - German School and Workshop 2007 (JIGSAW ’07), TIFR,Mumbai, India, February, 2007.

8. Prospects of INO with Beams, INO Collaboration meeting, University of Delhi,Delhi, India, March, 2007.

9. Neutrino mass hierarchy and θ13 with a magic baseline Beta Beam experiment,International Workshop on Theoretical High Energy Physics (IWTHEP) ,IIT, Roorkee, India, March, 2007.

Other Activities:

1. INO Training School, Seven tutorials on neutrino physics, April, 2006.

2. Participated in the “Topical Meeting on Physics at the LHC”, December,2006.

3. Pheno lunch review talks and extension talk.

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132

Arjun Bagchi

Research Summary:

I have joined the HRI String Theory Group this academic year and am work-ing under the supervision of Prof. Ashoke Sen. My specific area of research isTachyon Condensation and String Field Theory. In the first half of the year Ilooked at the new analytical solutions to the Bosonic String Field Theory by Mar-tin Schnabl and various other works related to it.

Presently, I am looking at the problem of formulating Superstring Field Theory onseparated D-brane-anti D-brane pair. Tachyon Condensation in superstring fieldtheories have been formulated on coincident brane-antibrane pairs and non-BPSD-branes in Type II theories. But in order to gain insight into actual formationof the tachyon and its condensation one needs to look at the separated case. Theanalysis now goes beyond the Universal sector and one needs to take into accountfields like the one responsible for the shifting of the branes. We have looked tosolve the problem in the Level Truncation scheme and are now looking at howone can put in time dependence into the game.


1. Advanced String Theory School, Institute of Physics, Bhubaneswar, September2006

2. Workshop on String Theory, HRI, December 2006.

3. Indian Strings Meet, Toshali Sands, Puri, December 2006.

4. Theoretical High Energy Physics SERC School, Hyderabad, January 2007.

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133

Priyotosh Bandyopadhyay

Research Summary:

I have been working in CP violating MSSM for the last one year. I’m trying toprobe the CPX point which was not ruled out by LEP in the small higgs massregion. The work is almost complete and we can say some thing positive aboutthat hole.

In the next projet I’ll be working in the non-universal gaugino mass scenario.Actually I want to see the effect of non-universal gaugino masses in the associatedhiggs productions.


1. Workshop on LHC Physics, TIFR, India, December, 2006

2. WIN07, SINP, Kolkata, India, January, 2007.


1. IACS, Kolkata, India, January, 2007

Other Activities:

1. I was tutor for QFT-II course in this academic year.

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Nabamita Banerjee

Research Summary:

My current research interests are:

a) The spectrum of dyons in a class of N=4 supersymmetric string theories hasbeen found for a specific set of electric and magnetic charge vectors. I extendthe analysis to a general charge vectors by considering various charge carryingcollective excitations of the original system. The charge vector I have taken isnot the most general one, so I am trying to make an analysis for a more generalcharge vector. It can change the counting altogether.

b) In 2-D string theory,the rolling tachyon states have been mapped to the fermionicstates of the corresponding Matrix model. This is a consequence of the open-closed duality. But to make the analysis complete, one needs to find what thehole states of matrix model corresponds to in 2-D string theory. I am trying tounderstand this issue.

c) I have been interested in studying the features of non-gravitating scalar fieldsand its uses to string compactification.

d) I am also studying the phase transition of the black holes (Ricci-flat) and itsconsequences in dual gauge theory by using AdS-CFT .

Preprints:

1. Nabamita Banerjee, Rajeev Jain, Dileep P. Jatkar: Non Gravitating ScalarField In FRW Background hep-th/0610109

2. Nabamita Banerjee, Dileep P. Jatkar, Ashoke Sen: Adding Charges to N=4Dyons (in preparation)

3. Nabamita Banerjee, Suvankar Dutta: Phase Transition of Electrically ChargedRicci-flat Black Holes (in preparation)

4. Nabamita Banerjee, Ashoke Sen: Hole State Correspondence In Matrix Model(in preparation)


1. Strings 2006, China, June, 2006.

2. Advanced Strings School, India, September, 2006.

3. Informal Workshop, on String Field Theory, India, HRI, 2006.

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4. ISM,Puri, India, December, 2006.

Other Activities:

1. Teaching Assistant in Math Method-1, August-December, 2006.

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136

Subhaditya Bhattacharya

Research Summary:

I have joined the HRI Particle Physics Phenomenology Group this academic yearand I am working under the supervision of Prof. Biswarup Mukhopadhyaya andDr. AseshKrishna Datta.I have been working on the Supersymmetric Extension of Standard Model, specif-ically on collider signatures at the LHC due to Non-universal gaugino massesat the GUT scale that arises in N=1 Supergravity framework due to non-trivialgauge kinetic function.


1. LHC Conference , Tata Institute of Fundamental Research, September 2006

2. Topical Meeting on Physics at the LHC, HRI, December 2006.

3. WIN07, Saha Institute of Nuclear Physics, January 2007.

Other Activities:I helped as a tutor in Computational Physics course taken by Dr. Prasenjit Sen forthe 2nd year 1st semester students(2006).I was also a tutor along with Arijit Saha in the course of Advanced Quantum Me-chanics instructed by Prof. Sumathi Rao for the 1st year 2nd Semester students(2006-2007).I gave a talk at the Pheno-Lunch at HRI on Supersymmetric Golden Region basedon the paper hep-ph/0702038. · · ·

137

Turbasu Biswas

Research Summary:

I have started working in string theory from this academic year. At present Iam reading Conformal Field Theory, specifically Logarithmic Conformal FieldTheory, with the aim of applying it to string theory. I have also done a readingproject on Quantum Hall Effect at the beginning of the academic year.


1. Advanced String Theory School, Institute of Physics, Bhubaneswar, September2006

2. Workshop on String Theory, HRI, December 2006.

3. Indian Strings Meeting 2006, Puri, December 2006.

4. SERC Main School on Theoretical High Energy Physics, Hyderabad, January2007.

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138

Suvankar Dutta

Research Summary:

1. My main research interest is AdS/CFT correspondence. In my last work withR. Gopakumar we examined the Euclidean action approach, as well as that ofWald, to the entropy of black holes in asymptotically AdS spaces. From thepoint of view of holography these two approaches are somewhat complemen-tary in spirit and it is not obvious why they should give the same answer inthe presence of arbitrary higher derivative gravity corrections. For the case ofthe AdS5 Schwarzschild black hole, we explicitly study the leading correction tothe Bekenstein-Hawking entropy in the presence of a variety of higher deriva-tive corrections studied in the literature, including the Type IIB R4 term. We finda non-trivial agreement between the two approaches in every case. Finally, wegive a general way of understanding the equivalence of these two approaches.2. Currently we are interested in the R charged black holes in five dimensionswhich are conjectured to be dual to the gauge theory defined on four dimensionswith chemical potential turned on. We are interested in the near-supersymmetricregion in the phase diagramme of these R charged black holes and studying thethermodynamics of these black holes and their dual gauge theory in this particu-lar limit.3. In a different project with N. Banerjee, we studied phase transition betweenelectrically charged Ricci-flat black holes and AdS soliton spacetime of Horowitzand Myers in five dimensions. Boundary topology for both of them is S1 × S1 ×R2.We also performed the stability analysis for these black holes.4. I am also working on AdS black holes and attractor mechanism in presence ofhigher derivative correction with D. Astefanesei, N. Banerjee, E. Radu.

Publications:

1. Suvankar Dutta, Rajesh Gopakumar, Euclidean and Noetherian Entropies inAdS space Physical Review Dvolume-number74:044007,2006

Preprints:

1. Nabamita Banerjee, Suvankar Dutta: Phase Transition of Electrically ChargedRicci-flat Black Holes (in preparation)

2. Suvankar Dutta, Rajesh Gopakumar: Supersymmetric limit of R charged blackhole (in preparation)

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1. Strings 2006, China, June, 2006,

2. Advanced Strings School, India, September, 2006,

3. Informal Workshop, on String Field Theory, India, HRI, 2006,

4. ISM,Puri, India, December, 2006.


1. SINP, Kolkata. May, 2006


1. Euclidean and Noetherian Entropies in AdS space / talk, , SINP, Kolkata, May,2006.

2. Euclidean and Noetherian Entropies in AdS space Poster presentation, STRINGS2006, Beijing, 2006.

3. Holography on Horizon and on Asymptotic Infinity / talk, ISM 06, Puri, Decem-ber, 2006.

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140

Pomita Ghoshal

Research Summary:

During this year, we have worked further on the analysis of the sensitivity tothe neutrino mass hierarchy using atmospheric neutrinos. We have attempted toevaluate the observability and experimental viability of these theoretically pre-dicted effects with the help of actual event rate calculations for some future detec-tors. Appreciable matter effects are observed in the muon survival events usingatmospheric neutrinos as the source. Also, taking into account the electron-likeevents leads to a large increase in the sensitivity to the mass hierarchy. Hence atpresent I am working on computing the sensitivity using both muon and electron-like events. This analysis has been performed for proposed atmospheric neutrinoexperiments using a large magnetized iron calorimeter detector like INO and amegaton Water Cerenkov detector like HyperKamiokande. I am working on in-cluding realistic estimates of the possible statistical and systematic errors in ouranalysis, and taking into account the resolution functions which smear the eventdistributions, thus affecting the sensitivity, as well as parameter uncertainties andcorrelations which may further reduce it. Further applications of this analysismay include future experiments involving superbeams and neutrino factories.

I have started working on a four-flavor analysis of atmospheric neutrino data.The three-flavor analytic expressions for the survival and oscillation probabilitiesas well as the numerical results are modified when a fourth sterile neutrino istaken into account. I am working on a study of how the results at the probabilitylevel are affected in a four-flavor scenario.

Preprints:

1. R. Gandhi, P. Ghoshal, S. Goswami, P. Mehta, S. Shalgar, S. Uma Sankar,Mass Hierarchy Determination via Atmospheric Neutrino Detectors (in prepara-tion)


1. Topical Meeting on Physics at the LHC, Harish-chandra Research Institute, Al-lahabad, India, December, 2006.

2. 21st International Workshop on Weak Interactions and Neutrinos (WIN07), SahaInstitute of Nuclear Physics, Kolkata, India, January, 2007.

3. Joint Indo-German School And Workshop (JIGSAW 2007), Tata Institute of Fun-damental Research, Mumbai, India, February, 2007.

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1. Munich Technical University, Munich, Germany, May - June, 2006.

Other Activities:

1. Worked as a tutor for the course taken by Raj Gandhi in Electrodynamicsfor first year students in H.R.I, August - December, 2006.

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142

Rajesh Kumar Gupta

Research Summary:

During last year, I have studied Introductory String theory, N = 2 supergravityin 4-dim. and Black Holes in string theory.At present I am trying to see the effect of field redefinition on 3-dim. pure super-gravity which we obtained by dimensionally reducing 5-dim. N = 2 supergrav-ity.


1. Advanced String school, IOP, Bhubaneswar, September, 2006

2. Workshop on String theory, HRI, December, 2006

3. Indian Strings Meeting, Toshali Sands, Puri, December, 2006

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143

Sudhir Kumar Gupta

Research Summary:

Throughout the year, I was mainly focusing on a supersymmetric scenario inwhich right handed sneutrinos are the lightest supersymmetric particles as op-posed to the conventional supersymmetric models. We (Biswarup Mukhopad-hyaya, Santosh K Rai and me) studied collider signatures of such a scenario inthe framework of minimal Supergarvity in the context of Large Hadron Collider(LHC).

Recently, we (Asesh Datta, Paramita Dey, Biswarup Mukhopadhyaya, AndreasNyffeler and me) initiated studies related with the distinction of Little Higgsmodels with supersymmetry at the LHC.

Publications:

1. Sudhir K Gupta, Biswarup Mukhopadhyaya and Santosh K Rai, Distin-guishing split supersymmetry in Higgs signals at the large hadron collider, Physi-cal Review D 73, 075006, (2006)

2. Sudhir K Gupta, Biswarup Mukhopadhyaya and Santosh K Rai, Right-chiralsneutrinos and long-lived staus: Event characteristics at the large hadron collider,Physical Review D 75, 075007, (2007)

Conference/Workshops/Schools Attended:

1. Expecting LHC, ICTP, Triste, Itly, September, 2006

2. Asian school on particles, strings and Cosmology, Nasu, Japan, September,2006.

3. Topical meeting on LHC, HRI, Allahabad, India, Feburary,2007.


1. Long Lived staus at the Large Hadron Collider [LHC], HRI, Allahabad, March,2007.

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144

Raghavendra Srikanth H

Research Summary:

During this current academic year I have concentrated on new physics at theTeV scale. I have worked in models like supersymmetry and little Higgs. I havetackled the following three problems.

• The data from neutrino oscillation experiments indicate that the neutrinomass is very small and the mixing pattern in the lepton sector is bilarge. Wehave tried to explain this data in a specific R-parity violating supersymmet-ric model, which is induced at the TeV scale by Planck scale physics.

• To explain the smallness of neutrino mass and the mixing pattern in thelepton sector, models based on lepton number violation by 2 units exist.From cosmological observations, there seem to exist an unknown matterwhich is different from the matter which we know. Can we understand thereasons for the existence of dark matter and the lepton number violation by2 units in a single theory? We have tried to understand this in a supergravitymodel.

• To explain the dark matter in the universe we need a weakly interacting,stable and neutral particle. In the littlest Higgs model with T-parity a natu-ral candidate for dark matter exists, which is known as heavy photon. Theanalogous particle in the minimal version of supersymmetry is neutralino.A Higgs boson can decay into a pair of heavy photons or neutralinos, de-pending on the model we consider. These decays are invisible. We havecomputed the invisible Higgs decay branching ratio in the littlest Higgsmodel with T-parity. We have found that this branching ratio is consid-erably larger than that in the minimal version of supersymmetry. We havepointed that this channel can be used to distinguish models which indicatenew physics at the TeV scale.

Publications:

1. Biswarup Mukhopadhyaya and Raghavendra Srikanth, Bilarge neutrino mix-ing in R-parity violating supersymmetry: The Role of right-chiral neutrino super-fields, Physical Review D 74, 075001, (2006)

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Preprints:

1. Biswarup Mukhopadhyaya, Soumitra SenGupta and Raghavendra Srikanth,Supergravity reconciles dark matter with lepton number violating neutrino masses,arXiv: hep-ph/0609304

2. Raghavendra Srikanth Hundi, Biswarup Mukhopadhyaya and Andreas Nyf-feler, Invisible Higgs boson decay in the Littlest Higgs model with T-parity, arXiv:hep-ph/0611116


1. Topical Meeting on Physics at the LHC, India, December, 2006.

2. WIN07, India, January, 2007.


1. Indian Association for the Cultivation of Science, Kolkata, India, July, 2006.

2. University of California, Riverside, USA, October, 2006.

3. University of Oregon, Eugene, USA, October, 2006.

4. University of Wisconsin, Madison, USA, October, 2006.

5. University of Illinois, Urbana-Champaign, USA, October, 2006.

6. University of Maryland, College Park, USA, October, 2006.

7. Syracuse University, Syracuse, USA, October, 2006.

8. Cornell University, Ithaca, USA, November, 2006.

9. Stanford Linear Accelerator Center, Menlo Park, USA, November, 2006.

10. Brookhaven National Laboratory, Upton, USA, November, 2006.

11. Fermi National Laboratory, Batavia, USA, November, 2006.


1. I gave seminars on Bilarge neutrino mixing and lepton number violation in su-persymmetric models at my visiting places in USA during October-November,2006.

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Rajeev Kumar Jain

Research Summary:

My research work is primarily focussed on understanding the origin and evo-lution of cosmological perturbations in inflationary scenarios and the resultingsignatures on the cosmic microwave background. The issues I have been study-ing during the last year are as follows:

1. Non-gravitating scalar field in the Friedmann universe

2. Amplification of tachyonic perturbations at super-Hubble scales

3. Generation of features in the primordial spectrum

4. Evolution of cosmological perturbations in bouncing universe

I have briefly described below the work I have completed which are listed as 1and 2 above. Issues 3 and 4 are still under investigation.

1. Non-gravitating scalar field in the Friedmann universe: In this work, we havestudied the evolution of an interacting scalar field that is coupled non-minimallyto gravity in a Friedmann universe. We have shown that for a specific choice ofthe parameters describing the interaction, the energy-momentum tensor of thescalar field vanishes and, as a result, the scalar field does not gravitate. The naivespace dependent solution to equations of motion gives rise to a singular field pro-file. We have carefully analyzed the energy-momentum tensor for such a solutionand have shown that the singularity of the solution leads to a subtle contributionto the energy-momentum tensor. The space dependent solution therefore is notnon-gravitating. Our conclusion is applicable to other space-time dependent non-gravitating solutions as well. We have also studied a hybrid inflation scenario inthis model when a purely time dependent and non-gravitating field is coupled toanother scalar field.

2. Amplification of tachyonic perturbations at super-Hubble scales: In the slow-roll inflationary scenario, the amplitude of the curvature perturbations approachesa constant value soon after the modes leave the Hubble radius. However, re-cently, it was shown that the amplitude of the curvature perturbations inducedby the canonical scalar field can grow at super-Hubble scales if there is either atransition to fast roll inflation or if inflation is interrupted for some period of time.In this work, we have extended the earlier analysis to the case of a scalar field de-scribed by the Dirac-Born-Infeld action. With the help of a specific example, wehave shown that the amplitude of the tachyonic perturbations grows at super-Hubble scales when there is a transition from slow roll to fast roll inflation. We

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have also illustrated as to how the growth of the entropy perturbations acts as thesource for the amplification of the curvature perturbations during the period offast roll inflation. Furthermore, following an earlier result for the canonical scalarfield, we have obtained a general criterion for the amplification of the tachyonicperturbations.

Preprints:1. Nabamita Banerjee, Rajeev Kumar Jain and Dileep P. Jatkar, Non-gravitating

scalar field in the FRW background, arXiv:hep-th/0610109.

2. Rajeev Kumar Jain, P. Chingangbam and L. Sriramkumar, Amplification oftachyonic perturbations at super-Hubble scales, arXiv:astro-ph/0703762.

Conference/Workshops Attended:1. IUCAA Reference Centre Workshop on Advanced Topics in Data Analysis in Cos-

mology and Gravitational Wave Astronomy, New Delhi, India, October, 2006.

2. 24th meeting of Indian Association for General Relativity and Gravitation, NewDelhi, India, February 2007.

Invited Lectures/Seminars:1. Amplification of tachyonic perturbations at super-Hubble scales, 24th meeting

of Indian Association for General Relativity and Gravitation, Jamia MilliaIslamia, New Delhi, India, February, 2007.

Other Activities:1. Astrophysics Journal Club Talk

(a) Can the tensor-to-scalar ratio be enhanced?, Journal club talk, April, 2006.(b) Symmetry and inflation, Journal club talk, September, 2006.

2. Astrophysics Seminar

(a) Scale-free spectra from non-vacuum initial states, Astrophysics Seminar,April, 2006.

3. A talk on ‘Gravitation’ in Rajbhasha school, HRI during May, 2006.

4. Helped in organizing and evaluating the papers (Physics) of HRI ScienceTalent Test 2006.

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Nishikanta Khandai

Research Summary:

Observational cosmology has made significant advances in the last decade andthese observations provide useful constraints for theoretical models. Large-scaleproperties of the Universe can be understood using perturbation theory whilesmall scale inhomogeneities become non-linear early on in their evolution andhave to be studied using N-body simulations. There are further complicationsintroduced by limitations of observations at these scales. The next generation oftelescopes will reveal much on the formation of structures at these scales.

To understand structure formation and make proper predictions for these tele-scopes one requires N-body algorithms which are not only accurate and efficientbut have a large dynamic range.

N-body Simulations: We are working on the Adaptive TreePM algorithm (ATreePM),an improvement over the existing TreePM algorithm of Bagla,J.S. (JAA.23:185-196, 2002), by introducing a variable softening length for the force, which willhelp resolve smaller scales. To do this one has to compute the local densityaround every particle. We are in the process of incorporating an efficient den-sity routine in the existing TreePM algorithm.

Before implementing ATreePM with all the modules that are in hand now, itwould be wise to further optimize them. We have managed to speedup TreePMby a factor of ∼ 2 − 3 by introducing a hierarchy of timesteps to integrate thetrajectories of particles. Further work is on to empirically determine the optimalvalues of the simulation parameters, which are crucial for speeding up the code.

The cost for going from TreePM to ATreePM, in terms of memory and speed,will be 2-3 times that of TreePM. But the resolution that we improve upon willbe effectively that of an order of magnitude larger (8-10) TreePM simulation. Inaddition, introducing a variable softening length for computing forces will keepthe same errors (in force, potential, density etc.) for all particles (i.e in overdenseas well as underdense regions) We hope to have a sequential implementation ofATreePM ready in a few months time.


1. Workshop on Study of Emission from Hot Diffuse Gas with Astrosat, Christ Col-lege and Raman Research Institute, Bangalore, 27 December 2006 - 3 Jan-uary 2007

2. Young Astronomer’s Meet, IIA Bangalore, 3-5 January 2007

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1. Adaptive TreePM, A High Resolution Collisionless Code for Cosmological N-BodySimulations, Young Astronomer’s Meet, Indian Institute of Astrophysics, Ban-galore, India, January 2007.

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Swarup Kumar Majee

Research Summary:

My current research interest lies on the topic of Universal Extra Dimension (UED),Supersymmetry Higgs search and Supersymmetric Grand Unified Theory in highenergy particle physics. During 2006-07, I have worked on the following topics –

(1) Power law scaling in Universal Extra Dimension scenariosCollaborators: Gautam Bhattacharyya, Anindya Datta, Amitava RaychaudhuriWe study the power law running of gauge, Yukawa and quartic scalar couplingsin the universal extra dimension scenario where the extra dimension is accessedby all the standard model fields. After compactifying on an S1/Z2 orbifold, wecompute one-loop contributions of the relevant Kaluza-Klein (KK) towers to theabove couplings up to a cutoff scale Λ. Beyond the scale of inverse radius, oncethe KK states are excited, these couplings exhibit power law dependence on Λ.As a result of faster running, the gauge couplings tend to unify at a relatively lowscale, and we choose our cutoff also around that scale. For example, for a radiusR ∼ 1TeV −1, the cutoff is around 30 TeV. We then examine the consequences ofpower law running on the triviality and vacuum stability bounds on the Higgsmass. We also comment that the supersymmetric extension of the scenario re-quires R−1 to be larger than ∼ 1010 GeV in order that the gauge couplings remainperturbative up to the scale where they tend to unify.

(2) Low Intermediate Scales for Leptogenesis in Supersymmetric SO(10) GrandUnified TheoriesCollaborators: Mina K. Parida, Amitava Raychaudhuri, Utpal SarkarA low intermediate scale within minimal supersymmetric SO(10) GUTs is a desir-able feature to accommodate leptogenesis. We explore this possibility in modelswhere the intermediate gauge symmetry breaks spontaneously by (a) doubletHiggs scalars and also (b) by triplets. In both scenarios gauge coupling unifi-cation requires the scale of left-right symmetry breaking (MR) to be close to theunification scale. This will entail unnaturally small neutrino Yukawa couplingsto avoid the gravitino problem and allow successful leptogenesis. We point outthat any one of three options – threshold corrections due to the mass spectrumnear the unification scale, gravity induced non-renormalizable operators near thePlanck scale, or presence of additional light Higgs multiplets – can permit uni-fication along with much lower values of MR as required for leptogenesis. Inthe triplet model, independent of these corrections, we find a lower bound onthe intermediate scale, MR > 109 GeV, arising from the requirement that the the-ory must remain perturbative at least upto the GUT scale. We show that in thedoublet model MR can even be in the TeV region which, apart from permitting

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resonant leptogenesis, can be tested at LHC and ILC.

(3) Extra-dimensional relaxation of the upper limit of the lightest supersym-metric neutral Higgs massCollaborators: Gautam Bhattacharyya, Amitava RaychaudhuriThe upper limit on the mass of the lightest CP-even neutral Higgs in a super-symmetric theory with two Higgs doublets is around 135 GeV. We demonstratethat this upper limit may be sizably relaxed, even by few tens of GeV, if super-symmetry is embedded in extra dimensions. We calculate, using the effectivepotential technique, the radiative corrections to the lightest Higgs mass inducedby the Kaluza-Klein towers of quarks and squarks with one and two compactifieddirections.

Publications:

1. Gautam Bhattacharyya, Anindya Datta, Swarup Kumar Majee, AmitavaRaychaudhuri, Power law scaling in universal extra dimension scenarios , Nu-clear Physics B760 , 117-127, (2006)

2. Swarup Kumar Majee, M. K. Parida, Amitava Raychaudhuri, Utpal Sarkar,Low intermediate scales for leptogenesis in supersymmetric SO(10) grand unifiedtheories, Phys. Rev. D75,075003, (2007)

3. M.K. Parida et al Working group report: Flavor physics and model building, Pra-mana 67, 849-860, (2006).

Preprints:

1. Gautam Bhattacharyya, Swarup Kumar Majee, Amitava Raychaudhuri Extra-dimensional relaxation of the upper limit of the lightest supersymmetric neutralhiggs, (in preparation)


1. Workshop on LHC Physics, TIFR, India, September, 2006,

2. 17th DAE-BRNS Symposium on HEP, IIT KHARAGPUR, India, December,2006.,

3. Topical Meeting on Physics at the LHC, HRI, India, December, 2006,

4. 21st International Workshop on Weak Interactions and Neutrinos (WIN07), SINP,Kolkata, India, January, 2007.

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5. International Workshop on Theoretical High Energy Physics (IWTHEP), IIT Roor-kee, India, March, 2007.


1. Power law scaling in the UED model, 17th DAE-BRNS Symposium on HEP,IIT KHARAGPUR, India, December 2006.

2. Power law scaling in the UED model, 21st International Workshop on WeakInteractions and Neutrinos (WIN07), SINP, Kolkata, January 2007.

Other Activities:

1. Tutor on the the course Relativistic Quantuam Mechanics and particle physicsin the 1st phase of INO Training School, April, 2006.

2. Pheno lunch review talk (a)Dark Matter in Universal Extra Dimension Mod-els: γKK Vs. νR,KK [hep-ph/0604154], May, 2006

(b)Solving problems of 4D minimal SO(10) model in a warped extra dimen-sion [hep-ph/0702048], February, 2007

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Kalpataru Pradhan

Research Summary:

1. Extending our previous work on Kondo Lattice Model (KLM), we focuson intermediate coupling regime where neither the perturbative RKKY ap-proach nor double exchange is valid. We are able to uncover the planarspiral states, A and C type of antiferromagnetic order along with ferromag-netic and G type antiferromagnetic order accompanied by phase separationbetween different phases using variational calculations. Using full spin-fermion Monte Carlo ( Traveling Cluster Approximation), we also map outthe ground state and estimate the ordering temperature, transport proper-ties and spectral features of the model. We discuss our results in the contextof the ‘heavy rare earth’ 4f elements, which are class of materials with ‘largeS’ magnetic moments coupled to 5d-6s conduction electrons via exchangeinteraction. The systematic increase of the 4f spin from Yb to Gd can bemapped out on to a variation of the effective exchange in our classical KLMand we suggest that these metals involve physics well beyond the RKKYinteraction regime as one moves from Yb to Gd in rare earth family.

2. The complicated interplay of spin, charge, lattice and orbital degrees of free-dom is believed to induce unexpected magnetic and transport phenomenain manganese oxides of the form (R,A)BO3 (R for Rare Earth Element, Afor Alkaline Earth Element and B for Manganese). The difference betweenA and B site disorder holds a key to the phase separation and spatial in-homogeneity in the manganites. In half doped manganites with A typedisorder, with randomly placed R and A elements, converts the CO-OO-CE-I ( Charge Order-Orbital Order-Zigzag pattern of ferromagnetic chains-Insulator) to a short range correlated glass. But the substitution of Mn byfew percents of Cr or Ru ( B site disorder) leads to metalicity with coexis-tence of FM-M (Ferromagnetic Metal) and CO-OO-AF-I domains. We studya two orbital double-exchange model in two dimensions in the presence ofantiferromagnetic superexchange, Jahn-Teller Coupling and substitutionaldisorder. We compare the impact of weak homogeneous disorder to that ofa low density of strong scatterers on CO-OO-CE-I at half doping. Even mod-erate homogeneous disorder suppresses the CO-OO-CE phase and leads toglass which is more or less a strong insulator with nano scale correlations.Dilute strong scatterers of comparable strength leads to coexistence of FM-M and CO-OO-AF clusters. This in turn lead to metalicity. It also seems thatmagnetic character of the B site impurity plays a important role at differentdoping.

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3. In search of clusters with large magnetic moments, we dope transition met-als (TM) to the Na clusters (motivated from large magnetic moments onTM doped with small gold clusters). Our central focus is to find groundstate atomic,electronic structures and most importantly magnetic momentsof Sc, Ti, V on small size Na clusters of size n (n=5,6) using Density Func-tional Theory (DFT). Interestingly we found Ti@Nan and V@Nan posseslarge magnetic moments, larger than atomic moments of Ti and V respec-tively. The origin of such unusual large magnetic moments is due to largeoverlap of Na s and TM d orbitals, and the relative values of electronega-tivity of the Na and TM atoms. We also find large magnetic moments withother TM like Cr, Mn and Fe doping in these clusters. We are doing a sys-tematic size dependent analysis of Na clusters doped with different TM.

Preprints:

1. Kalpataru Pradhan and Pinaki Majumdar, The classical Kondo Lattice at inter-mediate Coupling (preprint)

2. Kalpataru Pradhan and Pinaki Majumdar, Magnetism Beyond RKKY Interac-tion: Revisiting the 4f Metals (preprint)

3. Kalpataru Pradhan and Prasenjit Sen, Unexpectedly large magnetic momentson TM@Nan clusters (TM=Sc,Ti,V; n=5,6) (preprint)

4. Kalpataru Pradhan, Anamitra Mukherjee and Pinaki Majumdar, The distinctEffect of Homogeneous Weak Disorder and Dilute Strong Scatterers on Phase Com-petition in the manganites (preprint, Submitted to PRL)


1. Summer School on Electronic Structure Methods and their Applications, and Work-shp on Computational Materials theory, Bangalore,India, 10-22 July 2006.

2. International Conference on Physics Near The Mott Transition, Bangalore,India,24-28 July,2006.

3. Workshop on Correlated Systems and Novel Materials, Kharagpur,India, 16-18January,2007.

Other Activities:

1. Condensed Matter talk on The Kondo lattice with classical spins: magnetism,transport and dilution effects

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2. Condensed Matter talk on Hypothetical Zincblende Structure of MnAs: A Den-sity Functional Calculation

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156

Jayanti Prasad

Research Summary:

For the last one year I have been working on some problems related to non-lineargravitational clustering in an expanding universe. The main motivation behindthis study has been to understand how cosmological perturbations which lead togalaxy formation at various scales couple to each other. It has been known forquite a long time that the cosmological perturbations at small scales do not affectthe growth of perturbations at large scales in any significant way. This meansthat in cosmological simulations the truncation of initial power spectrum at smallscales due to the limitation of resolution at small scales does not contribute anysignificant error in the final results. However, that is not true for the truncationof power spectrum at large scales due to finite box size.

With my supervisor Jasjeet Singh Bagla I have developed an analytic techniqueto quantify the errors in various physical quantities due to finite box size in cos-mological N-body simulations. We have shown that the errors in most of thephysical quantities of interest like two-point correlation function and mass func-tion can be related to the errors in the mass variance or any second moment ofthe density contrast. We have shown that the mass variance is suppressed at allscales when we reduce the size of the simulation box and this results in the over-production of the low mass haloes at the expense of the underproduction of largemass haloes in cosmological N-body simulations.

In one of the studies I have shown that using the Press-Schechter formalism wecan write the rate of change of the number density of haloes of a given massin terms of the formation and destruction rates. Using the technique which wehave developed I have obtained the corrections due to finite box size in the cos-mological N-body simulations for the rate of change of density, formation anddestruction rates for a power law and LCDM models.

Publications:

1. J. S. Bagla and Jayanti Prasad, Effects of the size of cosmological N-body simula-tions on physical quantities-I. Mass function, MNRAS 370, 993, (2006)

Preprints:

1. Jayanti Prasad, Effects of finite box size in cosmological N-body simulations II :Halo formation and destruction rates, astro-ph/0702557)

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1. Summer School in Cosmology and Astroparticle Physics,The Abdus Salam In-ternational Centre for Theoretical Physics, Trieste, Italy, July 2006.

2. Workshop on study of emission from hot diffuse gas with ASTROSAT, Bangalore,India , January 2007.


1. The Abdus Salam International Centre for Theoretical Physics, Trieste, Italy,July, 2006

Other Activities:

1. Gave a short presentation in the ICTP Summer school in Cosmology andAstroparticle physics, July, 2006.

2. Gave seminar in the Astrophysical Journal Club at HRI, February, 2007.

3. I have been involved in the Talent Search Examination conducted by HRIfor school students.

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158

Arijit Saha

Research Summary:

[1] We study adiabatic charge pumping through a quantum dot placed at thejunction of N quantum wires. We find out that the pumped charge in this casehas a quantized value called winding number contribution and a non-integer partcalled the dissipative part. We explicitly map out the pattern of pumped charge asa function of the time-varying tunneling parameters coupling the wires to the dotand the phase between any two time varying parameters controlling the shape ofthe dot. We find that with N − 2 time-independent well-coupled leads, the max-imum pumped charge in the remaining two leads is strongly suppressed withincreasing N due to leakage through the other wires, leading to the possibility oftuning of the pumped charge, by modulating the coupling of the N − 2 leads.

[2] We study the effect of dephasing on adiabatic pumped charge through a dot atthe junction of multiple quantum wires. We make the phase of one of the hoppingparameters inside the dot random which acts like a random electric field. We findout that the pumped charge for N = 2 wires is almost robust to the dephasingeffect, but surprisingly there is a gradual decrease of pumped charge for N = 3wire case.

Publications:

1. Shamik Banerjee, Anamitra Mukherjee, Sumathi Rao and Arijit Saha, Adia-batic charge pumping through a dot at the junction ofN quantum wires. Phys.Rev.B75,153407, (2007).

Preprints:

1. Anamitra Mukherjee, Sumathi Rao and Arijit Saha, Dephasing effect to trans-port through a quantum dot pump at the junction of multiple quantum wires.


1. Physics near Mott Transition, IISc(Bangalore), India, July, 24-28, 2006.

2. Strongly correlated electron systems and nano materials, IIT (Kharagpur),India, January, 16-18, 2007.


1. Indian Institute of Science, Bangalore, India, July 14-28, 2006.

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Other Activities:

1. Extension talk: Adiabatic charge pumping through a quantum dot at Y junction,April 27, 2006.

2. Cond-mat lunch talk: Arbitrary ratio of pumped charge and spin current througha mesoscopic structure, September, 2006.

3. Class room talk: Graphene: Carbon in two dimensions, February, 2007.

4. Tutor for Advanced quantum mechanics course, Jan-April, 2007.

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160

Bindusar Sahoo

Research Summary:

I have worked on two problems in the academic year 2006-2007 which are asfollows:

1) α′-Corrections to Extremal Dyonic Black Holes in Heterotic String Theory. Thiswork was done in collaboration with Ashoke Sen. In this paper we worked outthe black hole entropy for heterotic string theory compactified on T 6 or K3 × T 2

by taking into account all the tree level four derivative terms and found propermatching with earlier results both for supersymmetric as well as non-supersymmetricblack holes.

2) AdS3, Black Holes and Higher Derivative Corrections. This work was done incollaboration with Justin David and Ashoke Sen. In this work we used ADS/CFTto prove that a 3 dimension supergravity theory having (0,4) supersymmetry can-not receive any further higher derivative corrections apart from the terms whichcan be removed by field redefinition. Then we used this result and invarianceof Walds formula under field redefinition to argue the non-renormalizability ofblack hole entropy of a BTZ black hole in three dimensional supergravity with(0,4) supersymmetry

Publications:

1. Bindusar Sahoo and Ashoke Sen, α′-Corrections to Extremal Dyonic Black Holesin Heterotic String Theory, JHEP 0701, 010, (2007)

Preprints:

1. Justin R. David, Bindusar Sahoo and Ashoke Sen, AdS3, Black Holes andHigher Derivative Corrections , arXiv:0705.0735


1. Informal Workshop on String theory, HRI, Allahabad , India, December 2006

2. Indian Strings Meeting, Toshali Sands, Puri, India, December 2006.

3. International Workshop on Theoretical High Energy Physics, IIT Roorkee, India,March 2007

4. IPM String School and Workshop, Tehran, Iran, April 2007

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1. Role of Chern Simons terms in Black Hole Entropy, Indian Strings Meeting,Jointly organized by the Indian String theory community, Puri, December2006.

2. Non-Supersymmetric Extremal Black Holes in Curvature squared N=2 Supergrav-ity , IWTHEP’07, IIT Roorkee, Roorkee, March 2007.

Other Activities:

1. Attended the Advanced Strings School held at the Institute of Physics, Bhubaneswar,October, 2006.

2. Gave a talk on “AdS3, Black holes and Higher derivative corrections”, as apart of the requirement of the Graduate programme, April, 2007.

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162

Anurag Tripathi

Research Summary:

My current research interest includes calculation of differential cross-section forHiggs production at NLO, for beyond SM models in general, and gravity medi-ated models in specific, which can be tested at LHC.I am also interested in Resummation programme, implemented using EffectiveField Theory approach, in particular SCET (Soft-Colliner-Effective-Theory).

Calculation of fixed order cross-section at NLO, for gravity mediated models forHiggs boson production at LHC is under progress using technique of the Two-Cutoff-Phase-Space-Slicing-Method.


1. CTEQ School 2006, Greece, July 2006

2. Workshop on LHC Physics, TIFR India, September 2006

3. SERC School in High Energy Physics, India, January 2007

Other Activities:

1. Two review talk for Effective Field theory Discussion Group, March, 2007.

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LECTURES / TALKS / SEMINARS

AT THE INSTITUTE

MATHEMATICS

1. Ioulia Baoulina On diagonal equations over finite fields

2. Basudeb Datta Triangulations of the torus and the Kleinbottle with vertex-transitive group actions

3. Ravi Kulkarni Dynamical Types and Conjugacy of Centralizersin Groups

4. Hidekazu Furusho p-adic analogue of multiple zeta values

5. Dipendra Prasad Some questions on Modular forms

6. Manoj Kr. Yadav A conjecture on automorphisms of finitep - groups

7. K. Varadarajan Series of Lectures on Group Rings

8. T. D. Browning Representation of integers by quadraticforms

9. H. A. Helfgott How small must ill-distributed sets be?(a two dimensional larger sieve)

10. C. S. Dalawat Congruent Numbers

11. A. Belov Polynomial automorphisms, Jacobian, Dixmierand Kontzevich

12. Riddhi Shah Some Properties of Operator-semistable ProbabilityMeasures on Real and P-adic Vector Spaces

13. Wolfgang Schmid Introduction to non-unique factorizationtheory

164

14. Sergei Loktev Finite-dimensional representations of multi-variable current algebras

15. Wolfgang Schmid Non-Unique Factorization Theory

16. T. N. Shorey A series of lectures on Linear forms in logarithmsand its applications

17. Yonggao Chen On the parity of exponents in the standardfactorization of n!

18. Christian Mauduit The sun of digits of prime numbers

19. Henri Darmon Some questions about cm elliptic curves

20. Roy Joshua A series of lectures on Etale Cohomology

21. W. Krawcewicz Equivariant Degree and its applications - 1

22. W. Krawcewicz Equivariant Degree and its applications - 2

23. Joseph Oesterle Why do Antennas emit Waves

24. Ram Murty Logic, Number Theory, and the Limits of HumanReason

25. J. Oesterle A series of ten lectures on Moduli space of genuszero curves with n marked points

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LECTURES / TALKS / SEMINARSAT THE INSTITUTE

PHYSICS

1. Nabamita Banerjee Plane Wave/Super Yang-Mills Duality

2. Suvankar Dutta On Euclidean and Noetherian Entropies in AdSSpace

3. Bindusar Sahoo Extremal Black Holes in the presence ofHigher Derivative Corrections

4. Priyotosh Bandopadhyaya Asymptotic Nature in Non-AbelianGauge Theory

5. Rishikesh Vaidya b→ s+ γ in Supersymmetrywithout R-parity

6. J. S. Bagla Observational Constraints on Models ofReionsation

7. K. Subramanian Physics of the Cosmic MicrowavesBackground Radiation

8. S. S. Deshingkar Evolution of Binary Black Hole Spacetimes

9. A. K. Mishra Metal-Insulator transition in an adsorbed layerat an Electrochemical Interface

10. A. K. Mishra Ortho-Fermi Quantum Statistics and its applicationsto the Infinite- U Hubbard Model

11. Arnab Kr. Ray Hydraulic/Shock Jumps in Proto-Planetary Disks

12. H. K. Jassal The Paths of Quintessence

13. Soumitra SenGupta Stability and hierarchy problems in a back-reacted Randall-Sundrum braneworld

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14. Sumathi Rao Free electron model

15. Prasenjit Sen Band Theory

16. T. P. Pareek Phonons

17. Prasenjit Sen Electron- electron interactions

18. Sumathi Rao/ MesoscopicsT. P. Pareek

19. M. Gopalkrishnan Stochastic processes

20. Prasenjit Sen Nanoscale materials

21. Manoj Gopalkrishnan Random Walk

22. Manoj Gopalkrishnan Non-equilibrium Stat. Mech.

23. Resham Sarkar Particle detectors in a high-energycollider

24. T. Roy Choudhury Studying Cosmic Reionisation withRecent Observations

25. Subir K. Das Critical Dynamics in Fluids: VerifyingTheory through Simulations

26. R. Nityananda Deconvolution

27. M. K. Parida Neutrino Mixing Angles and Leptonic CPViolation from Quark Mixing Matrix

28. Shivam Ghosh Association and rebinding of ligandsto a spherical cell surface

29. Nishikanta Khandai Collisions, Hyperfine transition ofHydrogen and the Spin Temperature

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30. Jayajit Das Early and late signaling events during Tcell activation

31. Jayanti Prasad Early Supersymmetric Cold Dark MatterSubstructure

32. J.S. Bagla Revisiting the Baryon Fractions of GalaxyClusters

33. Rajarshi Ray QCD Thermodynamics: Lattice and PNJL model

34. Tapas Das See a Black Hole on a Shoestring

35. Subharthi Ray Effects of the non-circular beams in theCMB power spectrum

36. L. Sriramkumar Synchrotron radiation from Crab: A constrainton Lorentz violation beyond the Planck scale!

37. Monodeep Chakraborty Study of the one dimensional Holstein modelusing the augmented space approach

38. Monodeep Chakraborty The study of electronic and magnetic propertiesof the partially disordered pseudo-Heusler alloyCo2Fe0.4Cr0.6Al: an augmented space approach

39. S. S. Deshingkar Inspiral, merger and ring-down of equal-mass black-holebinaries

40. K. Narayan Cosmologies with null Bing-Bang singularities and theirgauge theory duals

41. Jayajit Das Early and late signaling events during T cell activation

42. L. Sriramkumar Synchrotron radiation from Crab: A constraint on Lorentzviolation beyond the Planck scale!

43. S. N. Khanna Superatorms as the Building Blocks of Novel Nano-assembled Materials

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44. L. Sriramkumar Synchrotron radiation from Crab: A constraint on Lorentzviolation beyond the Planck scale!

45. Paramita Barai Modeling the Power Evolution of Classical Double RadioGalaxies over Cosmological Scales

46. Biswajoy Brahmachari Zee model of neutrino mass: In different flavors

47. S. Shankaranarayanan Entanglement as the source of black-hole entropy

48. Debaprasad Maity Stability analysis of the Randall-Sundrum brane worldwith bulk scalar field

49. Otto Kong Towards the Theory of Special Quantum Relativity

50. A. Gopakumar Inspiral dynamics of compact binaries: its applicationsand implications

51. Gianluca Calcagni Ghost conditions for Gauss-Bonnet cosmologies

52. Jayanti Prasad Superclusters of galaxies in the 2dF redshift survey

53. J. S. Bagla Looking for Dark Matter

54. Niklas Beisert The S-matrix of AdS/CFT

55. Nishikanta Khandai An Energy-Conserving Formalism for Adaptive GravitationalForce Softening in SPH and N-Body Codes

56. Arijit Bhattacharyay Modeling active motion in living systems

57. Arunansu Sil Thermal inflation and the flux of primordial monopoles

169

58. D. P. Roy Prospects of charged Higgs boson discovery at colliders

59. Sanjib Kr. Agarwalla Neutrino mass hierarchy and Θ13 with a magicbaseline beta-beam experiment

60. S. S. Deshingkar Kicks from Black-Hole Binaries

61. P. K. Mohanty Heat Conduction in one-dimension: Old wine in a new bottle

62. S. K. Gupta Long lived staus at the LHC

63. Peter West A lecture series on E11 and the Symmetries of M-Theory

64. S. T. Petcov Leptogenesis and Low Energy CP-Violation inthe Lepton Sector

65. Werner Rodejohann Structure of Neutrino Mixing and Quark-LeptonComplementarity

170

COLLOQUIUMJOINTLY ORGANISED BY

MATHS & PHYSICS

1. J. K. Bhattacharjee Divergent Critical Viscosity: ConvergentTheory and Experiment

2. K. Subramanian Magneto-Genesis in the Universe

3. Kamal Datta Einstein, Classical and Modern: Atomism, Relativityand Quantum Mechanics

4. Somdatta Sinha Modelling Biological Systems

5. Tarun Souradeep Celebrating the Cosmic Microwave Background

6. Swara Ravindranath Observational Constraints on GalaxyFormation from Deep Surveys

7. Sergei Loktev Space of Diagonal Harmonics

8. Nils-Peter Skoruppa On the Physics of the Rogers-RamanujanIdentities

9. T. Senthil Quantum criticality beyond the Landau-Ginzburg- Wilson paradigm

10. Henri Darmon Elliptic curves and periods of modular forms - 1

11. Gyan Bhanot Inferring Common Origins: How clustering andprincipal component analysis reveal the migrationhistory of humans out of Africa

12. Henri Darmon Elliptic curves and periods of modular forms - 2

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13. A. Gopakumar Gravitational Wave Astronomy

14. Maury Goodman The Neutrino Oscillation Industry

15. Debashish Chowdhury Interacting self-propelled particles: frommolecules to vehicles

16. Ram Ramaswamy Finding genes ( and other things) in DNA sequences:Mathematical methods for genomic analysis

172

PUBLICATIONS AND PREPRINTS

IN MATHEMATICS

PUBLICATIONS :

Sukumar Das Adhikari

1. Sukumar Das Adhikari and Purusottam Rath, Davenport constant with weightsand some related questions Integers, 6 paper A 30, (2006).

2. S. D. Adhikari and Y. G. Chen, Davenport constant with weights and some re-lated questions - II, J. Combinatorial Theory, Ser. A, doi: 10.1016/j.jcta.2007.03.004(2007).

3. Sukumar Das Adhikari and Purusottam Rath, Zero-sum problems in combina-torial number theory, The Riemann Zeta Function and Related Themes: Pa-pers in Honour of Professor K. Ramachandra, Proceedings of internationalconf. held at National Institute of Advanced Studies (Bangalore, 13-15 De-cember 2003), (Eds. by R. Balasubramanian and K. Srinivas), RamanujanMathematical Society Lecture Notes Series, Number 2, 1– 14, (2006).

4. S. D. Adhikari, R. Balasubramanian, F. Pappalardi and P. Rath, Some zero-sum constants with weights, Proc. Indian Acad. Sci. (Math. Sci.), to appear.

5. Sukumar Das Adhikari, Stephan Baier and Purusottam Rath, An extremalproblem in lattice point combinatorics, Diophantine Equations, N. Saradha Ed.,Tata Institute of Fundamental Research, to appear.

6. S. D. Adhikari, R. Balasubramanian and P. Rath, Some combinatorial group in-variants and their generalizations with weights, CRM Proceedings and LectureNotes, Granville, Nathanson, Solymosi Eds., to appear.

Kalyan Chakraborty

1. Kalyan Chakraborty, Florian Luca and Anirban Mukhopadhyay, Exponentsof class groups of real quadratic fields, International Journal Of Number Theory,To Appear, (2007)

2. Kalyan Chakraborty On the Diophantine equation x+y+z = xyz = 1 , AnnalesUniv. Sci. Budapest. Sect. Comp., 27, To Appear, (2007)

173

Chandan Singh Dalawat1. Congruent numbers, elliptic curves, and the passage from the local to the global,

to appear in the Proceeding of the Ramanujan Mathematical Society work-shop, Hyderabad, 3–5 July 2005.

Satya Deo1. Satya Deo and J.K.Maitra Freeness of homogenized spline module from a divided

domain to a subdivided domain, Frontiers in Interpolation and ApproximationEditor, N.K.Govil et al, Francis and Taylor, (2006)

2. Satya Deo and J.K.Maitra, Hilbert Series of free spline modules, Journal of In-dian Math Soc 73, page number, (2006)

3. Satya Deo, Algebraic Topology- a Primer, TRIM Series of Hindustan BookAgency, New Delhi, IInd Edition, 2006

Rukmini dey1. Rukmini Dey, Geometric quantization of the moduli space of the self-duality equa-

tions on a Riemann surface

Reports on Mathematical Physics Vol. 57 no. 2, pg. 179-188 (2006)

math-phy/0605026

2. Rukmini Dey, Geometric prequantization of the moduli space of the vortex equa-tions on a Riemann surface

Journal of Mathematical Physics, vol. 47, issue 10, page 103501

math-phy/0605025

Gyan Prakash1. R. Balasubramanian and Gyan Prakash, Asymptotic formula for sum-free sets

in abelian groups, Acta Arithmetica, Vol. 127, No. 2, 115-124, 2007.

N. Raghavendra1. Indranil Biswas and N. Raghavendra, The Atiyah-Weil criterion for holo-

morphic connections, Accepted for publication in the Indian Journal for Pureand Applied Mathematics.

B. Ramakrishnan1. (with B. Sahu) On the Fourier Expansions of Jacobi Forms of Half-Integral

Weight, Int. J. Math. Math. Sci. Vol 2006.

174

Ritumoni Sarma

1. Ritumoni Sarma, On Virtual 3-Generation of S-Arithmetic Subgroups of SL2,Asian Journal of Mathematics Vol. 10, No. 4, pp. 749-756.

R. Thangadurai

1. W. D. Gao and R. Thangadurai, On zero-sum Sequences of prescribed length,Aequationes Math., 72, 201-212, (2006)

2. R. Thangadurai, A variant of Davenport’s Constant, Proc. Indian. Acad. Sci.(Math. Sci.), 117, 1-11, (2007)

3. W. D. Gao, Q. H. Hou, W. A. Schmid and R. Thangadurai, On short zero-sumsubsequences - II, Integers, 7 A-21, 22pp, (2007)

Manoj Kumar Yadav

1. E. C. Dade and Manoj K. Yadav, Finite groups with many product conjugacyclasses, Israel J. Math. 154, 29-49, (2006)

Brundaban Sahu

1. B.Sahu and B. Ramakrishnan, On the Fourier Expansions of Jacobi Forms ofHalf-Integral Weight, Int. J. Math. Math. Sci. Vol 2006.

175

PREPRINTS :

Punita Batra

• Tanusree Pal, Punita Batra Irreducible integrable representations of graded multiloop Lie Algebras, http://arxiv.org/abs/0706.0448v1

Kalyan Chakraborty

• Kalyan Chakraborty, Florian Luca and Anirban Mukhopadhyay, Class num-bers of number fields with many distinct prime factors, (Preprint).

Satya Deo

• Satya Deo, David Gauld and Mathiew Baillif, Mapping Class Groups of somenonmetrizable manifolds,

• Satya Deo and V.V.Awasthi, Homology and Dimension -further pathological ex-amples

• Satya Deo and K. Varadarajan A note on Weakly Co-hopfian and generalizedHopfian modules

Rukmini dey

• Rukmini Dey, HyperKahler prequantization of the Hitchin systems and Chern-Simons gauge theory with complex gauge group (in preparation, draft in math-phy/06050270)

Ratnakumar Peetta Kandy

• Ratnakumar P.K., On Schrodinger propagator for the special hermite operator,preprint, (submitted for publication)

• Ratnakumar P.K., On Schrodinger propagator for differential operators with dis-crete spectrum, (in preparation)

• Ratnakumar P.K., Ritumoni Sarma, A cosine formula for the geometry of rankone symmetric spaces, (in preparation)

176

Gyan Prakash

• R. Balasubramanian, Gyan Prakash and D.S. Ramana, Sum-free subsets offinite abelian groups of type III, in preparation.

• Jean-Marc Deshouillers and Gyan Prakash, Large zero-free and incomplete sub-sets of Z/pZ, in preparation.

• Gyan Prakash and D.S. Ramana, The Large Sieve Inequality for Quadratic Poly-nomial Amplitudes, http://arxiv.org/abs/0705.1739.

• Gyan Prakash and D.S. Ramana, Baier’s Variant of the Large Sieve Inequalityfor Quadratic Polynomial Amplitudes, in preparation.

B. Ramakrishnan

• (with B. Sahu) Differential operators on Jacobi forms of several variable

• (with S. Gun, M. Manickam) A Characterization of the space of new formsof half-integral weight and a conjecture of Zagier.

• (with M. Manickam and V. Kumar Murty) Twisted averages of L-functions.

D. Surya Ramana

• D.S. Ramana,Arithmetical applications of an identity for the Vandermonde deter-minant, http://arxiv.org/abs/0705.1739.

• D.S. Ramana, Arcs of Conics Containing Three Integer Points,in preparation .

• R. Balasubramanian, Gyan Prakash and D.S. Ramana, Sum-free subsets offinite abelian groups of type III, in preparation .

• Gyan Prakash and D.S. Ramana, The Large Sieve Inequality for Quadratic Poly-nomial Amplitudes, http://arxiv.org/abs/0705.1739 .

• Gyan Prakash and D.S. Ramana, Baier’s Variant of the Large Sieve Inequalityfor Quadratic Polynomial Amplitudes, in preparation .

Ritumoni Sarma

• Ritumoni Sarma, Virtual 3-generation for S-arithmetic groups (in preparation).

• Ratnakumar P.K. and Ritumoni Sarma, A cosine formula for the rank one sym-metric spaces (in preparation).

177

R. Thangadurai

• S. Gun, F. Luca, P. Rath, B. Sahu and R. Thangadurai, Distribution of residuesmodulo p, Submitted for Publication.

• R. Thangadurai, Distribution of quadratic non-residues which are not primitiveroots modulo p - II, in preparation.

• P. Moree and R. Thangadurai, Distribution of quadratic non-residues which arenot primitive roots modulo p - III, in preparation.

Manoj Kumar Yadav

• Manoj K. Yadav, On automorphisms of finite p-groups, J. Group Theory, toappear

• Manoj K. Yadav, On automorphisms of some finite p-groups, Proc. Indian Acad.Sci., Math. Sci., to appear

Veerendra Vikram Awasthi

• Veerendra Vikram Awasthi and Satya Deo, An Inverse system of nonemptyobjects with empty limit, (communicated).

• Veerendra Vikram Awasthi and Satya Deo, Homology and Dimension - Furtherpathological examples, (under submission).

Tanusree Pal

• Tanusree Pal and Punita Batra, Irreducible Integrable Representations of GradedMulti-loop Lie Algebras. , arXiv:0706.0448v1 [math.RT]

Brundaban Sahu

• B. Sahu, B. Ramakrishnan, Differential operators on Jacobi form of several vari-able

• B. Sahu, S. Gun, Florian Luca, P. Rath and R. Thangadurai, Distribution ofResidues Modulo p.

178

PUBLICATIONS AND PREPRINTS

IN PHYSICS

PUBLICATIONS :

Jasjeet Singh Bagla1. Bagla J. S. and Prasad Jayanti, Effects of the size of cosmological N-Body simula-

tions on physical quantities — I: Mass Function, MNRAS 370, 993 (2006)

Sandhya Choubey1. Sanjib K. Agarwalla, Sandhya Choubey, Srubabati Goswami, Amitava Ray-

chaudhuri, Neutrino parameters from matter effects in in the nu(e) survival prob-ability long baselines, Phys. Rev. D 75, 097302 (2007).

2. Sanjib K. Agarwalla, Sandhya Choubey, Amitava Raychaudhuri, Neutrinomass hierarchy and theta(13) with a magic baseline beta-beam experiment, Nucl.Phys. B 771, 1 (2007).

3. Abhijit Bandyopadhyay, Sandhya Choubey, Srubabati Goswami, S.T. Pet-cov, Solar Model Parameters and Direct Measurements of Solar Neutrino Fluxes,to appear in Phys. Rev. D (2007).

4. Biswajoy Brahmachari, Sandhya Choubey, Modified Zee mass matrix withzero-sum condition, Phys. Lett. B 642, 495 (2006).

5. Sandhya Choubey, N.P. Harries, G.G. Ross, Probing neutrino oscillations fromsupernovae shock waves via the IceCube detector, Phys. Rev. D 74, 053010(2006).

Tapas K. Das1. Das, Tapas Kumar, Bilic, Neven, & Dasgupta, Surajit, Black-Hole Accretion

Disc as an Analogue Gravity Model, Journal of Cosmology & AstroparticlePhysics, 06, 009, (2007)

2. Goswami, Sanghamitra, Khan, Saba Nasreen, Ray, Arnab Kumar, & Das,Tapas Kumar, Axisymmetric black hole accretion in the Kerr metric as an au-tonomous dynamical system, Monthly Notices of the Royal Astronomical Soci-ety, 378, 1407, (2007)

179

3. Mandal, Ipsita, Ray, Arnab Kumar, & Das, Tapas Kumar, Critical propertiesof spherically symmetric black hole accretion in Schwarzschild geometry, MonthlyNotices of the Royal Astronomical Society, 378, 1400, (2007)

4. Barai, Paramita & Das, Tapas Kumar, Characterizing general relativistic tran-sonic astrophysical accretion in Kerr black holes, Proceedings of the XXIII TexasSymposium on Relativistic Astrophysics, Melbourne, Australia, 11th - 15th

December, 2006, To Appear, (2007)

5. Chaudhury, Soumini, Ray, Arnab Kumar, & Das, Tapas Kumar, Critical prop-erties and stability of stationary solutions in multi-transonic pseudo-Schwarzschildaccretion, Monthly Notices of the Royal Astronomical Society, 373, 146, (2006)

Justin R. David1. Justin R. David, Ashoke Sen, CHL Dyons and Statistical Entropy Function from

D1-D5 System, JHEP 0611 072, (2006).

2. Justin R. David, Rajesh Gopakumar, From spacetime to worldsheet: Four pointcorrelators, JHEP 0701 063, (2007).

3. Justin R. David, Dileep P. Jatkar, Ashoke Sen, Dyon Spectrum in N = 4 Su-persymmetric Type II String Theories, JHEP 0611 073, (2006).

4. Justin R. David, Dileep P. Jatkar, Ashoke Sen, Dyon spectrum in genericN = 4supersymmetric ZN orbifolds, JHEP 0701 016, (2007).

Raj Gandhi

1. R. Gandhi and S. Panda, “Probing the cosmic ray ’knee’ and very high en-ergy prompt muon and neutrino fluxes via underground muons,” JCAP0607, 011 (2006) [arXiv:hep-ph/0512179].

2. R. Gandhi and W. Winter, “Physics with a very long neutrino factory base-line,” Phys. Rev. D 75, 053002 (2007) [arXiv:hep-ph/0612158].

3. R. Gandhi et al., “Working Group Report: Astroparticle And Neutrino Physics,”Pramana 67, 735 (2006).

180

Debashis Ghoshal

1. D. Ghoshal, p-Adic string theories provide discretization to the ordinary stringworldsheet, Phys. Rev. Lett. 97, 151601, (2006).

2. B. Ezhuthachan and D. Ghoshal, Generalised HyperKahler Manifolds in StringTheory , J. High Energy Phys.04, 083, (2007).

3. D. Ghoshal, p-Strings vs. strings, in Mathematical Physics: Proceedings ofthe 12th Regional Conference, Islamabad, Pakistan, 2006, Eds. M. JamilAslam et al, World Scientific (2007).

Rajesh Gopakumar1. J. R. David and R. Gopakumar, From spacetime to worldsheet: Four point corre-

lators JHEP 0701, 63 (2007).

2. S. Dutta and R. Gopakumar, On Euclidean and Noetherian entropies in AdSspace Phys. Rev. D 044007, (2006).

3. R. Dijkgraaf, R. Gopakumar, H. Ooguri and C. Vafa, Baby universes and stringtheory, Conference Proceedings of Workshop on Einstein’s Legacy, ToshaliSands. Int. J. Mod. Phys. D.15, 1581, (2006).

Manoj Gopalakrishnan1. Manoj Gopalakrishnan, Peter Borowski, Martin Zapotocky and Frank Julicher,

Response and fluctuations of a two-state signaling module with feedback, Phys.Rev. E (2007, in press)

Srubabati Goswami

1. A. Bandyopadhyay, S. Choubey, S. Goswami and S. T. Petcov , Solar modelparameters and direct measurements of solar neutrino fluxes, Phys. Rev. D 75,093007, (2007)

2. S. K. Agarwalla, S. Choubey, S. Goswami and A. Raychaudhuri, Neutrinoparameters from matter effects in Pee at long baselines, Phys. Rev. D 75, 097302(2007)

3. A. Dighe, S. Goswami and W. Rodejohann Corrections to Tri-bimaximal Neu-trino Mixing: Renormalization and Planck Scale Effects, Phys. Rev. D 75, 073023(2007)

181

4. R. Gandhi et al., Working Group Report: Astroparticle And Neutrino Physics,Pramana, 67, 735 (2006).

5. S. Goswami Physics potentials of a magnetized iron calorimeter detector, Phys.Scripta T127, 28 (2006).

6. S. Goswami and W. Rodejohann Constraining mass spectra with sterile neutri-nos from neutrinoless double beta decay, tritium beta decay and cosmology Phys.Rev. D 73, 113003 (2006).

7. A. Dighe, S. Goswami and P. Roy Quark-lepton complementarity with quaside-generate Majorana neutrinos, Phys. Rev. D 73, 071301 (2006)

Harvinder Kaur Jassal1. H. K. Jassal, L. Sriramkumar, Entropy of BTZ black strings using the brick-wall

approach, Class. Quantum Grav. 24, 2589 (2007).

Dileep Jatkar1. J. R. David, D. P. Jatkar and A. Sen, Dyon Spectrum in N=4 Supersymmetric

Type II String Theories, JHEP 0611, 073, (2006)

2. J. R. David, D. P. Jatkar and A. Sen, Dyon Spectrum in Generic N=4 Supersym-metric ZN Orbifolds, JHEP 0701, 016, (2007)

Pinaki Majumdar1. Sanjeev Kumar, Arno P. Kampf and Pinaki Majumdar, Domain Formation and

Orbital Ordering Transition in a Doped Jahn-Teller Insulator, Phys. Rev. Lett.97, 176403, (2006)

2. Sanjeev Kumar, Arno P. Kampf and Pinaki Majumdar, The Effect of Disorderin an Orbitally Ordered Jahn-Teller Insulator, Phys. Rev. B 75, 014209, (2007)

Biswarup Mukhopadhyaya1. Sudhir Kumar Gupta, Biswarup Mukhopadhyaya, Santosh Kumar Rai, Right-

chiral sneutrinos and long-lived staus: Event characteristics at the large hadroncollider, Phys. Rev. D75, 075007 (2007).

2. Raghavendra Srikanth Hundi, Biswarup Mukhopadhyaya, Andreas Nyf-feler Invisible Higgs boson decay in the Littlest Higgs model with T-parity, Phys.Lett B649, 280 (2007).

182

3. Biswarup Mukhopadhyaya, Raghavendra Srikanth, Bi-large neutrino mixingin R-parity violating supersymmetry: The Role of right-chiral neutrino superfields,Phys. Rev. D74, 075001 (2006).

4. Sudhir Kumar Gupta, Biswarup Mukhopadhyaya, Santosh Kumar Rai, Dis-tinguishing split supersymmetry in Higgs signals at the large hadron collider,Phys. Rev D73, 075006 (2006).

Andreas Nyffeler1. R.S. Hundi, B. Mukhopadhyaya and A. Nyffeler, Invisible Higgs boson decay

in the littlest Higgs model with T-parity, Phys. Lett. B 649, 280, (2007)

Sudhakar Panda1. M.de Roo, D.B. Westra and Sudhakar Panda, Gauging CSO groups in N = 4

supergravity, JHEP 09, 011, (2006)

2. Sudhakar Panda, Vacua in N = 4 gauged supergravity, Mathematical PhysicsProc. 12th regional conf. Islamabad, 190, (2006)

Tribhuvan P. Pareek1. T. P. Pareek, Spin-orbit-induced torque in a collinear spin valve: A possible route

to design fast magnetic memory, PRB 75, 115308, (2007)

2. T. P. Pareek, . Measuring Spin Hall conductance and Rashba spin orbit interactionvia electrical measurement in Y shape conductor. , To appear in IJMPB volume-number, page number, (2007)

Mina Ketan Parida1. Adhikary, Biswajit, Brahmachari, Biswajoy, Ghosal, Ambar, Ma, Ernest &

Parida, M. K. A4 symmetry and prediction of Ue3 in a modified Altarelli-Ferugliomodel, Phys. Lett. B 638, 345 (2006).

2. Agarwalla, Sanjib Kumar, Parida, M. K., Mohapatra, R. N. & Rajasekaran,G. Neutrino mixings and leptonic CP-violation from CKM matrix and Majoranaphases, Phys. Rev. D 75 , 033007 (2007).

3. Majee, Swarup Kumar, Parida, Mina K. , Raychaudhuri Amitava & SarkarUtpal, Low intermediate scales for leptogenesis in supersymmetric SO(10) grandunified theory, Phys. Rev. D 75, 075003 (2007).

183

4. Parida, M. K. & Sinha, N. Working group report: Flavor physics and model build-ing, Pramana 67, 849 (2006).

Sumathi Rao1. Sourin Das, Sumathi Rao and Diptiman Sen, Effects of interactions and junc-

tions on conductances of quantum wires, in Special Issue on the International Con-ference on Nanoscience and Technology, eds. M. K. Sanyal, A. K. Raychaudhuriand D. Chakravorty, International Journal of Nanoscience 4 951 - 956, (2005).

2. Ravi Chandra, Sumathi Rao and Diptiman Sen, A multi-channel fixed pointfor a Kondo spin coupled to a junction of Luttinger liquids, Europhys. Lett. 75,797, (2006)

3. Ravi Chandra, Sumathi Rao and Diptiman Sen , Renormalisation group studyof the Kondo problem at a junction of several quantum wires Phys. Rev. B75,045435 (2007)

4. Shamik Banerjee, Anamitra Mukherji, Sumathi Rao and Arijit Saha Adiabaticcharge pumping through a dot at the junction of N quantum wires Phys. Rev.B75, 153407 (2007)

V. Ravindran1. J. Blumlein and V. Ravindran. O(α2

s) timelike Wilson coefficients for parton-fragmentation functions in Mellin space, Nucl.Phys.B749:1-24(2006), arXiv:hep-ph/0604019

2. M. C. Kumar, P. Mathews and V. Ravindran. PDF and scale uncertainties ofvarious DY distributions in ADD and RS models at hadron colliders, Eur.Phys.J.C49:599-611(2007), arXiv:hep-ph/0604135,

3. J. Blumlein and V. Ravindran. QCD threshold corrections to Higgs decay and tohadroproduction in l+l− annihilation, Phys.Lett.B640:40-47(2006), arXiv:hep-ph/0605011,

4. V. Ravindran, J. Smith and W. L. van Neerven, QCD threshold corrections todi-lepton and Higgs rapidity distributions beyond N 2LO, Nucl. Phys. B767,100-129(2007), arXiv:hep-ph/0608308

184

Amitava Raychaudhuri1. Rathin Adhikari, Sanjib Kumar Agarwalla, and Amitava Raychaudhuri,

Can R-parity violating supersymmetry be seen in long baseline beta-beam experi-ments?, Phys. Lett. B642, 111–118 (2006)

2. Gautam Bhattacharyya, Anindya Datta, Swarup Kumar Majee, and Ami-tava Raychaudhuri, Power law running in Universal Extra Dimension scenar-ios, Nucl. Phys. B760, 117-127 (2007)

3. Swarup Kumar Majee, Mina K. Parida, Amitava Raychaudhuri and UtpalSarkar, Low intermediate scales for leptogenesis in SUSY SO(10) GUTs, Phys.Rev. D75, 075003 (2007)

4. Sanjib Kumar Agarwalla, Subhendu Rakshit, and Amitava Raychaudhuri,Probing Lepton Number Violating Interactions with Beta-beams, Phys. Lett. B647,380-388 (2007)

5. Sanjib Kumar Agarwalla, Sandhya Choubey, and Amitava Raychaudhuri,Neutrino mass hierarchy and θ13 with a magic baseline beta-beam experiment,Nucl. Phys. B771, 1-27, 2007

Ashoke Sen

1. J. R. David and A. Sen, “CHL dyons and statistical entropy function fromD1-D5 system,” JHEP 0611, 072 (2006) [arXiv:hep-th/0605210].

2. D. Astefanesei, K. Goldstein, R. P. Jena, A. Sen and S. P. Trivedi, “Rotatingattractors,” JHEP 0610, 058 (2006) [arXiv:hep-th/0606244].

3. J. R. David, D. P. Jatkar and A. Sen, “Dyon spectrum in N = 4 supersymmet-ric type II string theories,” JHEP 0611, 073 (2006) [arXiv:hep-th/0607155].

4. B. Sahoo and A. Sen, “alpha’-Corrections to Extremal Dyonic Black Holesin Heterotic String Theory,” JHEP 0701, 010 (2007) [arXiv:hep-th/0608182].

5. J. R. David, D. P. Jatkar and A. Sen, “Dyon spectrum in generic N = 4 super-symmetric Z(N) orbifolds,” JHEP 0701, 016 (2007) [arXiv:hep-th/0609109].

6. A. Dabholkar, A. Sen and S. P. Trivedi, “Black hole microstates and attractorwithout supersymmetry,” JHEP 0701, 096 (2007) [arXiv:hep-th/0611143].

7. A. Dabholkar, N. Iizuka, A. Iqubal, A. Sen and M. Shigemori, “Spinningstrings as small black rings,” JHEP 0704, 017 (2007) [arXiv:hep-th/0611166].

185

8. A. Sen, “Walls of Marginal Stability and Dyon Spectrum in N=4 Supersym-metric String Theories,” 0705, 039 (2007) [arXiv:hep-th/0702141].

9. A. Sen, “Geometric tachyon to universal open string tachyon,” JHEP 0705,035 (2007) [arXiv:hep-th/0703157].

Prasenjit Sen1. Prasenjit Sen, Peierls instability and electron-phonon coupling in a one-dimensional

sodium wire, Chemical Physics Letters 428, 430, (2006)

L. Sriramkumar1. L. Sriramkumar and S. Shankaranarayanan, Path integral duality and Planck

scale corrections to the primordial spectrum in exponential inflation, JHEP 0612,050 (2006).

Sanjib Kumar Agarwalla1. Rathin Adhikari, Sanjib Kumar Agarwalla, Amitava Raychaudhuri, Can R-

parity violating supersymmetry be seen in long baseline beta-beam experiments?,Phys.Lett.B 642, 111-118, (2006)

2. Sanjib Kumar Agarwalla, Subhendu Rakshit, Amitava Raychaudhuri, Prob-ing Lepton Number Violating Interactions with Beta-beams., Phys.Lett.B 647,380-388, (2007)

3. Sanjib Kumar Agarwalla, Sandhya Choubey, Amitava Raychaudhuri, Neu-trino mass hierarchy and θ13 with a magic baseline beta-beam experiment., NuclearPhysics B 771, 1-27, (2007)

4. S.K. Agarwalla, M.K. Parida, R.N. Mohapatra, G. Rajasekaran, NeutrinoMixings and Leptonic CP Violation from CKM Matrix and Majorana Phases.,Phys.Rev.D 75, 033007, (2007)

Suvankar Dutta

1. Suvankar Dutta, Rajesh Gopakumar, Euclidean and Noetherian Entropies inAdS space Physical Review Dvolume-number74:044007,2006

186

Sudhir Kumar Gupta1. Sudhir K Gupta, Biswarup Mukhopadhyaya and Santosh K Rai, Distin-

guishing split supersymmetry in Higgs signals at the large hadron collider, Physi-cal Review D 73, 075006, (2006)

2. Sudhir K Gupta, Biswarup Mukhopadhyaya and Santosh K Rai, Right-chiralsneutrinos and long-lived staus: Event characteristics at the large hadron collider,Physical Review D 75, 075007, (2007)

Raghavendra Srikanth H.1. Biswarup Mukhopadhyaya and Raghavendra Srikanth, Bilarge neutrino mix-

ing in R-parity violating supersymmetry: The Role of right-chiral neutrino super-fields, Physical Review D 74, 075001, (2006)

Swarup Kumar Majee1. Swarup Kumar Majee, Gautam Bhattacharyya, Anindya Datta, Amitava

Raychaudhuri, Power law scaling in universal extra dimension scenarios , Nu-clear Physics B760 , 117-127, (2006)

2. Swarup Kumar Majee, M. K. Parida, Amitava Raychaudhuri, Utpal Sarkar,Low intermediate scales for leptogenesis in supersymmetric SO(10) grand unifiedtheories, Phys. Rev. D75,075003, (2007)

3. M.K. Parida et al Working group report: Flavor physics and model building, Pra-mana 67, 849-860, (2006).

Jayanti Prasad1. J. S. Bagla and Jayanti Prasad, Effects of the size of cosmological N-body simula-

tions on physical quantities-I. Mass function, MNRAS 370, 993, (2006)

Arijit Saha1. Shamik Banerjee, Anamitra Mukherjee, Sumathi Rao and Arijit Saha, Adia-

batic charge pumping through a dot at the junction ofN quantum wires. Phys.Rev.B75,153407, (2007).

Bindusar Sahoo1. Bindusar Sahoo and Ashoke Sen, α′-Corrections to Extremal Dyonic Black Holes

in Heterotic String Theory, JHEP 0701, 010, (2007)

187

PREPRINTS :

Jasjeet Singh Bagla• Bagla J. S. and Ray Suryadeep, Gravitational Clustering in Redshift Space: Non-

Gaussian Tail of the Cosmological Density Distribution Function, astro-ph/0604598.

Sandhya Choubey• Sandhya Choubey, N.P. Harries, G.G. Ross, Turbulent Supernova Shock Waves

and the Sterile Neutrino Signature in Megaton Water Detectors, hep-ph/0703092(under review in Phys. Rev. D).

• Sandhya Choubey, What we can learn from atmospheric neutrinos, arXiv:hep-ph/0609182.

• Sandhya Choubey and other members of ISS physics working group, In-ternational scoping study of a future Neutrino Factory and Super-beam facility.http://www.hep.ph.ic.ac.uk/iss/wg1-phys-phen/index.html

• Ram Lal Awasthi and Sandhya Choubey, Confusing Sterile Neutrinos withDeviation from Tribimaximal Mixing at Neutrino Telescopes, in preparation.

• M.Sajjad Athar et al, [INO Collaboration], India-based Neutrino Observatory:Project Report

Tapas Kumar Das• Bilic, Neven, Das, Tapas Kumar, & Ray, Suhrita, Analogue gravity effects in

pseudo-Schwarzschild shocked accretion disc, (Submitted).

• Bhattacharaya, Atri, Ray, Arnab Kumar, Bhattacharjee, Jayanta Kumar, Das,& Tapas Kumar, Critical dynamics of quasi-viscous transonic black hole accretion,(In preparation).

• Moscibrodzka, Monica, Das, Tapas Kumar, & Czerny, Bozena, On determi-nation of the spin of the Galactic centre black hole, (In preparation).

• Dasgupta, Surajit, Das, Tapas Kumar, & Rao, A. R., Possible identification ofCygnus X-3 as a Galactic microblazar, (In preparation).

• Das, Tapas Kumar, & Czerny, Bozena, Chaotic features of multi-transonicityand its effects on microvariability, (In preparation).

188

AseshKrishna Datta• Minimal Universal Extra Dimensions in CalcHEP/CompHEP, with K. Kong and

K.T. Matchev, (In preparation)

• On implications of high-scale nonuniversalities of gaugino masses at LHC, with S.Bhattacharya and B. Mukhopadhyaya (In preparation)

• On interesting signatures of CP-violating SUSY at LHC, with A. Datta, P. Ban-dopadhyay and B. Mukhopadhyaya (In preparation)

• On novel signatures of Little Higgs scenario (with T-parity) at LHC, with P. Dey,S.K. Gupta, B. Mukhopadhyaya and A. Nyffeler (In preparation)

Justin R. David• Ofer Aharony, Justin R. David, Rajesh Gopakumar, Zohar Komargodski ,

Shlomo S. Razamat, Comments on worldsheet theories dual to free large N gaugetheories hep-th/0703141.

Paramita Dey• Paramita Dey, Asmaa Abada, Gregory Moreau: Neutrinos in flat extra dimen-

sion: towards a realistic scenario hep-ph/0611200 (communicated to JHEP)

• Paramita Dey, Ritesh Singh: Top quark polarization as a probe of extra dimension(in preparation)

• Paramita Dey, Asesh Dutta, Sudhir K Gupta, Andreas Nyffeler, BiswarupMukhopadhyaya: Distinguishing the Little Higgs model with T-parity fromSupersymmetry at the LHC (in preparation)

• Paramita Dey, Biswarup Mukhopadhyaya, Anirban Kundu: Some Phenomeno-logical Aspects of a Doublet-Triplet Higgs Model (in preparation)

Raj Gandhi• M. S. Athar et al. [INO Collaboration], “India-based Neutrino Observatory:

Project Report. Volume I,”

• The ISS Physics Working Group, ”Physics at a Future Neutrino Factory andbeta-beam Facility” in preparation, current draft at http://www.hep.ph.ic.ac.uk/

189

• R. Gandhi, P. Ghoshal, S. Goswami, P. Mehta, S. Uma Sankar & S. Shal-gar, Mass Hierarchy Determination in future Atmospheric Neutrino Detectors,(In preparation).

Debashis Ghoshal• D. Ghoshal, Quantum extended arithmetic Veneziano amplitude, HRI-P-0604001,

AEI-2006-036, math-ph/0606003.

Rajesh Gopakumar• O. Aharony, J. David, R. Gopakumar, Z. Komargodsky and S. Razamat,

Comments on worldsheet theories dual to free large N gauge theories (hep-th/0703141,to appear in Phys. Rev. D.).

Manoj Gopalakrishnan• Shivam Ghosh, Manoj Gopalakrishnan and Kimberly Forsten-Williams, Self-

consistent stochastic theory of reversible ligand binding to a spherical cell surface(inpreparation).

• Bindu Govindan, Manoj Gopalakrishnan and Debashish Chowdhury En-hanced depolymerization of microtubules by MCAK proteins,(in preparation).c

Srubabati Goswami• M. S. Athar et al. [INO Collaboration], A Report of the INO Feasibility Study.

Updated from the earlier Interim Report of May 1, 2005,

• Srubabati Goswami and Werner Rodejohann MiniBooNE Results and Neu-trino Schemes with 2 sterile Neutrinos: Possible Mass Orderings and Observablesrelated to Neutrino Masses, in preparation

• Srubabati Goswami and Toshihiko Ota, Testing Non-Unitarity of NeutrinoMixing Matrices in Neutrino Factories, (in preparation)

• Raj Gandhi, Pomita Ghoshal, Srubabati Goswami, Poonam Mehta, S UmaSankar, Shashank Shalgar Mass Hierarchy determination via future AtmosphericNeutrino Detectors in preparation

Bindu S. Govindan

190

• Bindu S Govindan, Manoj Gopalakrishnan, Debashis Chowdhury Enhanceddepolymerization of microtubules by MCAK proteins (in preparation)

Dileep Prabhakar Jatkar• N. Banerjee, R. K. Jain and D. P. Jatkar, Non-Gravitating Scalar Field in the

FRW Background,

191

Pinaki Majumdar• Kalpataru Pradhan, Anamitra Mukherjee and Pinaki Majumdar, The Dis-

tinct Effects of Homogeneous Weak Disorder and Dilute Strong Scatterers on PhaseCompetition in the Manganites, submitted for publication

• Kalpataru Pradhan and Pinaki Majumdar, The Classical Kondo Lattice at In-termediate Coupling (in preparation)

• Kalpataru Pradhan and Pinaki Majumdar, Magnetism Beyond the Ruderman-Kittel-Kasuya-Yosida Interaction: Revisiting the 4f Metals (in preparation)

Biswarup Mukhopadhyaya• Rathin Adhikari, Anindya Datta, Biswarup Mukhopadhyaya, The neutrino

mass scale and the mixing angle θ13 for quasi-degenerate Majorana neutrinos, hep-ph/0703318.

• Biswarup Mukhopadhyaya, Soumitra SenGupta, Raghavendra Srikanth Hundi,Supergravity reconciles dark matter with lepton number violating neutrino masses,hep-ph/0609304.

Satchidananda Naik• The Open string formulation of N = 8 self-dual Super gravity (to appear soon)

Sudhakar Panda• M.de Roo, D.B. Westra and Sudhakar Panda, Gauging CSO groups in N = 4

supergravity, hep-th/0606282

• Sudhakar Panda, Vacua in N = 4 gauged supergravity, HRI-P-06-08-004

Tribuvan Prasad Pareek• T. P. Pareek and A. M. Jayannavar, Generation and Measurement of Non Equi-

librium Spin Currents in Two Terminal Systems,

Sumathi Rao• Anamitra Mukherji, Sumathi Rao and Arijit Saha, Transport through a quan-

tum dot pump at a multiple wire junction, (in preparation)

192

Amitava Raychaudhuri• Sanjib Kumar Agarwalla, Sandhya Choubey, Srubabati Goswami, and Ami-

tava Raychaudhuri, Neutrino parameters from matter effects in Pee at long base-lines, hep-ph/0611233, Phys. Rev. D (to appear)

• Abhijit Samanta, Sudeb Bhattacharya, Ambar Ghosal, Kamales Kar, Deba-sish Majumdar, and Amitava Raychaudhuri, A GEANT-based study of atmo-spheric neutrino oscillation parameters at INO, hep-ph/0702180

• M. Sajjad Athar et al., India-based Neutrino Observatory: Project Report. VolumeI, INO-2006-01

Prasenjit Sen• Kalpataru Pradhan and Prasenjit Sen, Unexpectedly large moments on TM@Nan

clusters: (TM=Sc, Ti, V; n = 5, 6),

L. Sriramkumar• H. K. Jassal and L. Sriramkumar, Entropy of BTZ black strings using the brick

wall approach, gr-qc/0611102.

• R. K. Jain, P. Chingangbam and L. Sriramkumar, Amplification of tachyonicperturbations at super-Hubble scales, astro-ph/0703762

Sanjib Kumar Agarwalla• Sanjib Kumar Agarwalla, Sandhya Choubey, Srubabati Goswami, Amitava

Raychaudhuri, Neutrino parameters from matter effects in the νe survival proba-bility at long baselines., hep-ph/0611233

Nabamita Banerjee• Nabamita Banerjee, Rajeev Jain, Dileep p. Jatkar: Non Gravitating Scalar

Field In FRW Background hep-th/0610109

• Nabamita Banerjee,Dileep P. Jatkar,Ashoke Sen: Adding Charges to N=4Dyons (in preparation)

• Nabamita Banerjee,Suvankar Dutta: Phase Transition of Electrically ChargedRicci-flat Black Holes (in preparation)

193

• Nabamita Banerjee, Ashoke Sen: Hole State Correspondence In Matrix Model(in preparation)

Suvankar Dutta• Nabamita Banerjee, Suvankar Dutta: Phase Transition of Electrically Charged

Ricci-flat Black Holes (in preparation)

• Suvankar Dutta, Rajesh Gopakumar: Supersymmetric limit of R charged blackhole (in preparation)

Pomita Ghoshal• R. Gandhi, P. Ghoshal, S. Goswami, P.Mehta, S. Shalgar, S. Uma Sankar,

Mass Hierarchy Determination via Atmospheric Neutrino Detectors (in prepara-tion)

Raghavendra Srikanth Hundi• Biswarup Mukhopadhyaya, Soumitra SenGupta and Raghavendra Srikanth,

Supergravity reconciles dark matter with lepton number violating neutrino masses,arXiv: hep-ph/0609304

• Raghavendra Srikanth Hundi, Biswarup Mukhopadhyaya and Andreas Nyf-feler, Invisible Higgs boson decay in the Littlest Higgs model with T-parity, arXiv:hep-ph/0611116

Rajeev Kumar Jain• Nabamita Banerjee, Rajeev Kumar Jain and Dileep P. Jatkar, Non-gravitating

scalar field in the FRW background, arXiv:hep-th/0610109.

• Rajeev Kumar Jain, P. Chingangbam and L. Sriramkumar, Amplification oftachyonic perturbations at super-Hubble scales, arXiv:astro-ph/0703762.

Swarup Kumar Majee• Swarup Kumar Majee, Gautam Bhattacharyya, Amitava Raychaudhuri Extra-

dimensional relaxation of the upper limit of the lightest supersymmetric neutralhiggs, (in preparation)

194

Kalpataru Pradhan• Kalpataru Pradhan and Pinaki Majumdar, The classical Kondo Lattice at inter-

mediate Coupling (preprint)

• Kalpataru Pradhan and Pinaki Majumdar, Magnetism Beyond RKKY Interac-tion: Revisiting the 4f Metals (preprint)

• Kalpataru Pradhan and Prasenjit Sen, Unexpectedly large magnetic momentson TM@Nan clusters (TM=Sc,Ti,V; n=5,6) (preprint)

• Kalpataru Pradhan, Anamitra Mukherjee and Pinaki Majumdar, The distinctEffect of Homogeneous Weak Disorder and Dilute Strong Scatterers on Phase Com-petition in the manganites (preprint, Submitted to PRL)

Arijit Saha• Anamitra Mukherjee, Sumathi Rao and Arijit Saha, Dephasing effect to trans-

port through a quantum dot pump at the junction of multiple quantum wires.

Bindusar Sahoo• Justin R. David, Bindusar Sahoo and Ashoke Sen, AdS3, Black Holes and

Higher Derivative Corrections , arXiv:0705.0735

195

ABOUT THE LIBRARY

The Institute’s library is one of the best equipped libraries in the region. Beinga research oriented institute, it provided the required support to the academicand research activities. It remained open on all working days from 8 am to 2am including the Saturdays. It also remained open during the Sundays andthe Gazetted holidays from 10 a.m. to 6 p.m. It had added 468 (four hundredsixty eight) volumes in its fold which includes 444 purchased books and 24 giftedbooks, it increases the total number of books to 15759. It has also added 639bound volumes of the journals during the period from 1st April 2006 to 31stMarch 2007, it has increased bound volumes collection to 27545. The institute’slibrary has a total collection of 43304 (Forty three thousand three hundred four)(B15759+J27545) of books and bound volumes. The library had subscribed 232journals during this period. It includes 107as online journals.

During the last year basic emphasis had been provided to the conversion of theVideo Cassettes to VCD format for durability. Recently the library web page hasbeen reconstructed which provides more detailed information about the librarysuch as subscribed databases, archives, library rules, library staff, list of onlinejournals, online link to the Video lectures and other useful links. The emphasiswas also given to procure maximum number of journals on line. We have beenproviding on-line access of the periodical to our users for 105(One hundred five)titles.

We had provided the Web Enabled library catalogue to our users. The library canbe termed as completely automated library system, which includes acquisition,cataloguing, circulation, search modules etc. This on-line catalogue had increasedthe opportunities of the use of our library resources by the neighboring organiza-tions such as INSDOC, TIFR etc. through the Document Delivery Services (DDS).Normally we provide the DDS on request through post, at very nominal cost, butrequests had also been honoured through e-mail. We had encouraged the use ofthe library by providing the library consultation facilities to the research scholarsfrom the neighboring institutes. We had strengthened our library security withthe implementation of Electro-magnetic Tattle Tapes to reduce the losses. It hasbeen completely functional.

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ABOUT COMPUTER SECTION

1. Expansion of the local area network in the students’ offices of the first floorlibrary building was commissioned and made operational.

2. 30 KVA ONLINE UPS system was purchased, installed and commissionedto provide the uninterrupted power supply in the offices of the first floorlibrary building.

3. 21 Desktops were purchased and installed with Linux operating system inthe offices of first floor library building.

4. A good quality A3 size colour laser printer was purchased and installed inthe computer centre.

5. A4 size laser printers were purchased and given to all the faculty members,accounts and administrative sections.

6. Campus area network was extended and commissioned to the newly con-structed E-Type flats.

7. Newer versions of different flavors of Linux operating systems were loadedon the desktops.

8. Few more laptops were procured for giving presentation and doing com-putation work while on visit.

9. Wireless networking was established in the Auditorium, Lecture hall, Li-brary lounge, meeting room and guest house for providing easy and mobileLAN and Internet connectivity.

10. Computing related to conferences were held in the conference computerroom.

Current Activities and plans

1. Purchase of more (4 Mbps/8 Mbps) Internet bandwidth is under process tosuffice the increased Internet usage.

2. Purchase of new desktops is under plan to upgrade the computer centredesktops.

3. Purchase of couple of new high end ONLINE central UPS is under plan toupgrade the old 20 KVA UPS systems.

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4. Purchase of a few colour duplex laser printers and mono duplex laser print-ers is under plan to upgrade the computer centre printers.

5. Expansion of wireless networking to cover up most of the places of Institutebuilding and library building is under plan.

6. Purchase of a few more laptops is under plan.

7. Upgradation of ERNET Internet link from VSAT SCPC to VSAT DAMA isunder process.

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CONSTRUCTION WORK AT THE CAMPUS

1. An exercise for Invitation of Expression of Interest for Project ConsultancyServices was done. Based on that five parties were selected. New tenderwas given to all selected parties for detailed engineering consulting servicesfor the work. After finalization of tender construction activities will start forthe following buildings (Hostel-3, Institute expansion, Community CentreAnnexe and Engineering building).

2. Since power roistering is increasing every year therefore Institute is nowtrying to set 33 KVA uninterrupted power supply line directly from 132KVA Substation (Hanumanganj). In this connection Institute has depositedthe estimated amount given by UPPCL for further action.

3. Following miscellaneous works were carried out during this financial year:-

• Marble flooring for auditorium lobby.

• Construction of room for ATM.

• Construction of 1.5M wide pathway along the boundary wall.

• Development of new lawn.

• Providing and fixing one additional wire mesh door shutter for Type-Ehouses.

• Providing and fixing enclosure around electronic security machine inLibrary building.

• Supplying and fixing 2mm thick PVC tile flooring in conference roomof Institute building.

• Fencing of HRI land near river side of Ganga with barbed wire.

• Providing and fixing fire hydrant near new Type-E quarters.

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VIGILANCE ACTIVITIES AT THE CAMPUS

There is nothing to report from vigilance point of view for the period upto March31, 2007.

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