international centre for theoretical phvsics · giambiagi said, "i have the honour to confer...

International Atomic Energy Agency

United Nations Educational, Scientific and Cultural Organization

International Centre for Theoretical Phvsics

No. 64i65 November/December 1992

Professor Pavel Bogolubw receiving the Dirac Medal of 1992 from Professor AbdusSalam, Director of the International Centre for Theoretical Physics and President of ThirdWorld Academy of Sciences, on 2 December 1992, in the Main Lecture llall of the (CTP. Onthz brt, Prof. JJ. Giarnbiagi, Mernber of the ICTP Scientiftc Council.

Dirac Medal Award Ceremony

On2December1992,oneofthe1992Dirac Medals which had been assigned(posthumously) to Professor NikolaiNikolaevich Bogolubov (Dubna,Russia), was presented to his son. Theother 1992 Dirac Medal will be awardedto Professor Yakov G. Sinai [-andauInstitute of Theoretical Physics,Moscow, Russia) during the 1993 HighEnergy Summer School. Two suchmedals are awarded every year on thebirthday of P.A.M. Dirac — 8th August.

The ceremony took place in the MainLecture Hall of the ICTP, Trieste, Italy.Professor Abdus Saiam, Director of theInternational Centre for TheoreticalPhysics [CTP) and President of theThird World Academy of Sciences(TWAS) presented the medal and a

cheque of US$ 5,000 to Professor PavelBogolubov, the son of Professor N.N.Bogolubov.

Professor N.N. Bogolubov ishonoured posthumously "in recognitionof his many fundamental contributions inphysics and mathematics. In statisticalphysics, his treatment of Bose-Einsteincondensation in a non-ideal gas was aseminal work which laid the basis for amicroscopic theory of superfluidity inHelium II. It stimulated many of the laterdevelopments using quasi-particlemethods. He later generalised thismethod tofermions and applied it to thephenomenon of superconductivityproviding a systematic microscopictheory. The famous Bogolubovtransformation is now a cornerstone of

Inside:Professor Abdus Salam APPointedas Emeritus Professor...............'.....2Cold Medal Award Ceremony 2Top Scorer in the ICTP Diplomac{}urse Pro"gramme l99L-92 3Interview lvith M. ArshadMomen 3t)st-gz ICTP Diploma ProgrammeEnds and New Academic YearBegins • 3ICTP Visiting Mathematician WinsMax-Planck Research Award 5Collaboration in Mathematics 5Atoms in Intense Laser Fie|ds 6Primo Rovis Prize 1992. . 8Interview with Peakash Khanal 8Second UN/ESA Workshop on IlasicSpace Science 9Role of Science in Indian Society .11Obituaries — Prols. A. Ilorsellinoand R. Marshak 12Activities at ICTP in November-December 12Calendar of Activities in 1993 15

modern physics. In elementary particlephysics, Bogolubov was the first to give arigourous proof, basedon local quantumfield theory, of fixed angle dispersionrelations for pion-nucleon scattering.This emerged from his study of theaxiomatic basis of relativistic quantumfield theory and the structure of the S-matrix. Another important result was asystematic formulation of therenormalisation programme forperturbative computations of the S-matrix. In mathematics, among his manyimportant contributions we cite his workon non-linear mechanics and the generaltheory of dynamical systems".

Professor N.N. Bogolubov was bornon21 August 1909 in Gorky. Attheageof 14 he wrote his first scientific paper

News from ICTP - No. 64165-November/December 1992

and in 1930 he received the degree ofDoctor of Mathematics. In 1948 Prof.Bogolubov was elected Member of theUkrainian Academy of Sciences and, in1953, Member of the Academy ofSciences of the USSR. Subsequently,Prof. Bogolubov became a Member ofthe Presidium of the Academy and Headof the Section of Mathematics and, in1964, Director of the Joint Institute forNuclear Research in Dubna.

Over a very long period of scientificresearch in mathematics and theoreticalphysics, he published more than 300papers. Prof. Bogolubov was awardedthe Lenin Prize (1958), the LomonosovPrize of the Academy of Sciences of theUSSR and received the highest awardsconferred by the Soviet Union. Hebecame an honorary member of manyscientific academies and was awardedseveral degrees honoris causa. Hereceived the Helmholz Golden Medal ofthe Academy of Science of the GermanDemocratic Republic (1969), the MaxPlanck Gold Medal of the PhysicalSociety of the Federal Republic ofGermany (1973), the Benjamin FranklinMedal (1974) and many other imporrantawards. . o . •

Professor JJ.Giambiagi presenting the plaquetteto Professor Abdus Salam. OnProfessorAbdus Salam's right, Prof. Pavel Bogolubov (Dubna, Russia).

Professor Abdus SalamAppointed as

Emeritus Professor

Gold Medal Award Ceremonv

On 3 December 1992, a gold medalwas awarded to Professor Abdus Salam,Director, International Centre forTheoretical Physics (ICTP) andPresident, Third World Academy ofSciences (TWAS), in the Main LectureHall of the ICTP, Trieste, by the SlovakAcademy of Sciences in Bratislava. Forthis purpose a Slovak delegation visitedthe ICTP. It was composed of ProfessorB. Frankovic, Vice-President of theSlovak Academy of Sciences, andProfessor S. Luby, Head of theDepartment of Physics of the sameAcademy.

The Slovak Academy of Sciences

decided to award a gold medal toProfessor Abdus Salam for hisengagement in science promotion andco-operation also in that country. In fact,the ICTP, the Slovak Academy ofSciences, and the Comenius Universityin Bratislava signed a co-operationagreement providing for a mutualexchange of scientists and researchers,according to which the ICTP bears theliving expenses of scientists fromBratislava while attending courses orcarrying out research at the ICTp.Similarly, the Slovak institution offersgrants towards the living expenses ofICTP Associates while in Bratislava. I

During the Dirac Medal Ceremonywhich was held on 2 December 1992 atthe Main Lecture Hall of the ICTP, Prof.J.J. Giambiagi, Director of ttre CentroLatinoamericano de Fisica and Memberof the ICTP Scientific Council,announced that Professor Abdus Salam,Director of the International Centre forTheoretical Physics and President of theThird World Academy of Sciences, hadbeen appointed as Emeritus Professor ofthe Centro Brasileiro de PesquisasFisicas, Rio de Janeiro, Brdzil.

As he presented a special plaquettefor this occasion, Prof. J.J. Giambiagisaid, "I have the honour to confer you thetitle of Emeritus Professor of CBPF toexpress in a concrete form ourrecognition for your scientificachievements as well as your tirelesssupport for fte development of science inthe developing countries".

This award had the unanimoussupport of the Brazilian community ofphysicists in recognition of all the effortsProfessor Abdus Salam has made for thedevelopment of physics in Brazil. r

News from ICTP - No. 64165 - November/December 1992

Top Scorer in the ICTPDiploma Course

Programme, l99l-92

Mr. Arshad Momen (Bangladesh),who was a participant of the l99l-92Diploma Programme held at the ICTP,scored the top position among 20participants. He was a participant in theHigh Energy Physics course. Followinghis brilliant success in this course, he gota research fellowship for his Ph.D. atSyracuse University, New York.

Mr. Arshad Momen completed hisB.Sc. (Hons.) in the Department ofPhysics, University of Dhaka,Bangladesh, and also scored top positionfor his outstanding performance in thatuniversity.

He has completed several researchpapers with hofessor A.M. Harun-ar-Rashid, Department of Physics,University of Dhaka (also SeniorAssociate, ICTP). For his Diplomadissertation he worked with Professor S.Randjbar-Daemi,ICTP. |

Interview withM. Arshad Momen

Mr. Arshad Momen

Q.: Let me first of all congratulateyou for the fine work you have donetowards the Diploma Course of ICTP.The Certificate was awarded to vou on

25th September'92. Could you describeyour reaction?

A.: Thank you. I am really glad tobe able !o complete all the trainings thatwearesupposedtodo. It.givesmeasenseof achievement.

Q.: What are your lmpresslonsabout the Course?

A.: The Course has beenparticularly useful for me to clarifycertain topics which had remained quite'fiJzzy' to me for a long time, while I wastrying to learn at home by myself. It alsogives an opportunity to learn lots ofthings from eminent physicists at ICTP.

Q.: In what way will the Courseinfluence your future career?

A.: Well, surely it has helped toenter a graduate school. Apart from that,Iwillbeable to comprehend many thingsfaster than my fellow students, I guess.One thing that l must mention is that hereI worked on a subject for my dissertationwhich is on the interface of condensedmatter and high energy physics, forwhich I had to interact with people fromthe condensed matter group as well.Thus, I now have a wide outlook towardsphysics.

Q.: Could you please brieflydescribe your research work ordissertation?

A.: Well, as I told earlier—it has todo with the interface of high energyphysics and condensed matter. It wasshown quite recently that the two-dimensional string theory admits aninfinite symmery called W- infinity. Wetried to look for this symmery in ttrequantum Hall effect and what would beits consequences.

Q.: Did you give any lecture orseminar at ICTP? If so, kindly illustrateit briefly.

A.: Unfortunately, I should say no.However, as a part of our program, eachof the high energy physics student had rogive a talk on something for thecosmology examination. I gave apresentation on the "CosmologicalConstant Problem".

Q.: Would you have any academicsuggestion for future participants in theDiploma Course?

A.: The only thing I would suggestthem is to take the course seriouslv and

ry to leam things from the people aroundas much as possible.

Q.: You have spent one year inTrieste. What are your impressionsabout ICTP?

A.: What amazes me is the size ofthe institution especially when I thinkthat a person like Prof. Salam has donethis almost single-handedly. I think thisis really a remarkable achievement byitself. However, speaking frankly, theonly problem that it faced is the financialcrisis and that is because, I think, it hadexpanded too fast. I hope despite thefinancial problems the ICTP will stillflourish and contribute to scientificdevelopment throughout the world.

Thanks. o •

l99l-92 ICTP DiplomaProgramme Ends andNew Academic Year

Begins

The l99 l -92 ICTP DiplomaProgramme terminated as scheduled atthe end of September. The Centre'sDirector, Prof. Abdus Salam, met withdeparting participants to wish them wellin their continuing studies. He told theyoung scientists that they shouldconsider ttre hogramme irot as an end,but as the beginning of a life in physics:they will have to work very hard, butshould keep in mind that their efforts willeventually find reward, that they shoulddo well in their chosen field andafterwards help others who, likethemselves, often work in difficult andisolated conditions. It is important that inthe future they remember their homecountries and retum tlere to assist otherstudents. Healso suggested that they stayin contact with the numerous scientists— many of whom are highly-qualifiedand of renown — ttrat ttrey met duringtheir l2-month stay at ttre ICTP.

The one-year Diploma Coursesprogramme is geared to providing youngpromising graduates in physics and

continued on Page 5

3

News from ICTP - No. 64l65 - November/December 1992

The 1992-93 ICTP Diploma Programme in Brief

I October 1992 through 30 September 1993

Condensed Matter Physics

Co-ordinatorV. Kumar (kdia/ICTP)

High-Energy Physics

Co-ordbutorF. Hussain (PakistanllCTP)

Mathematics

Co-ordinatorC. Chidume (Nigeria/ICTP)

Topbs: Topbs: Topbs:

First term: (7 October - 22 December 79921:

Lattice VibrationsMany-Body PhysicsStatistical Mechanics & PhaseTransitionsSymmetry & Bands

General RelativityLie Groups & Lie Algebras IQuantum ElecaodynamicsQuarks & lrptonsRelativistic Quantum Mechanics

Differential GeometryMeasures & IntegrationPoint-set Topology

Second term: (4 Januam - Mavl.lune 79921:

Density Functional TheoryElectron GasMagnetismNonlinear Dynanicd SystemsSemiconductors & SuperlatticesSuperconductivity & Quasi -l-dimensional Systems

Theory of Complex Systems

Lie Groups & Lie Algebras trQuannm Field TheoryThe Standard ModelSupersymmetry & Grand UnifiedTheories

Algebra (Groups, Rings &Modules, Fields & Galois Theory)

Complex AnalysisFunctional AnalysisIntroduction to Algebraic GeometryIntroduction to Algebraic TopologyTheory of Ordinary Differential Equations

Faculty:

First term: P. Fazekas, Y. KumarG. Morandi, G. Santoro

Second. termz H. Cerdeira, P. Fazekas,N. Kumar, V. Kumar, A. Levi,M. Parisi M. Tosi, Yu Lu

Faculty:

First term: G. Ellis, G. Furlan,E. Gav4 F. Hussain, J. Strathdee

Second term: G. Barbiellini,K. Narain, S. Randjbar-Daemi,G. Senjanovic, C. Verzegnassi

Faculty:

First term: E. Ciiza, D. Repovs,G. Vidossich, B. Zimmermann

Second term: M. Brundu, C. Chidume,A. [,ogar, E. Mezzetti, M. Pontecorvo,D. Repovs, G. Vidossich, B. Zimmermann.

Participants:

l.E.R. Camacho (Peru)2. Chan Minh Tien (Vietnam)3. A.J. Ekpunobi (Nigeria)4. H.F. El-Nashar (Egypt)5. H.T.K. Hang (Viet Nam)6. S.W. Hla (Ihailand)7. S.I. Khondaker @angladesh)8. J:W. Kutor (Ghana)9. SJ.H. Shah (Pakistan)10. ,K. Uprety (Nepal)11. D.Yurdabak (Iurkey)

Participants:

1. M. Ahmed (Pakistan)2. T. Alemu (Ethiopia)3. H. Blas (Peru)4. A. Husain (Pakistan)5. E.L Lashin (Eeypt)6. J.H. I lon (Peru)7. A. Melfo (Venezuela)8. C.I. Ogu (Nigeria)9. B.M.Oktay (Turkey)10. O.Y. Osman (Sudan)11. K.D. Pance (Albania)12. S. Periaranda (Cuba)

Participants:

1.M.Akil (Syria)2. M.I. Beynah (Somalia)3. S.C. Bhowmik (Bangladesh)4. A.A. Hussein (Somalia)5.M. Kabanda (Zaire)6. D. L,e Dung (Viet Nam)7. M.O. Osilike (Nigeria)8. M.S. Rahman @angladesh)9. P. Tahmasebi (kan)10. C.J. Verjovsky (Mexico)


cofiinued from Page 3

mathematics an advanced level ofraining suitable for pursuing furtherteaching and research work. Of the 20students who took part in the CondensedMatter Physics and High-Energy Physicscomponents in this first academic year,17 were awarded the ICTP Diploma.Some of these have been accepted inGraduate Studies programmes in suchwell-known institutions as SyracuseUniversity in New York, the IndianInstitute of Science in Bangalore, and theInternational School of AdvancedStudies in Trieste. Others retumed totheir home countries to continue theirhigher education there and/or to study forGRE and TOEFL examinations requiredfor enrolment in other prestigiousinstitutions.

The second ICTP Diploma Courseprogramme regularly began on 1 October1992 and will continue through 30September 1993. This year, theMathematics component is also in fullswing, bringing the total number ofparticipants to 33 (11 in CondensedMatter Physics, 12 in High-EnergyPhysics, and 10 in Mathematics). Due tothe already recognized usefulness of theprogramme, a number of these studentshave come to Trieste under scholarshipsoffered by other institutions.

This year, the basic (first-term)courses in Condensed Matter Physicsinclude I"attice Vibrations, Many-Body

Physics, Statistical Mechanics and PhaseTransitions, and Symmery and Bands.Those in High-Energy Physics deal withGeneral Relativity, Introduction to LieGroups and Lie Algebras, QuantumElectrodynamics, Quarks and Leptons,and Relativistic Quantum Mechanics.First-term courses in Mathematics arededicated to Differential Geometry,Measures and Integration, and Point-setTopology.

More advanced lecture series,planned for the period January to May/June 1993, will be as follows:in Condensed Matter Physics: DensityFunctional Theory, Electron Gas,Nonlinear Dynamical Systems,Semiconductors and Superlattices,Superconductivity and Quasi-l-dimensional Systems, Surfaces andInterfaces, and Theory of ComplexSystems.in High-Energy Physics: Lie Groups andLie Algebras II, Quantum Field Theory,Standard Model, and Supersymmetryand Grand Unified Theories.in Mathematics: Algebra (Groups,Ringsand Modules, Fields and Galois Theory),Complex Analysis, Functional Analysis,Introduction to Algebraic Geometry,Introduction to Algebraic Topology, andTheory of Ordinary DifferentialEquations.

Special topics lectures will also bedelivered, and students are expected toparticipate in other scheduled activitiesof the Cenfre in the three fields.

As usual, after completion of thecourses and relevant examinations, fromMayflune until the end of September1993, Diploma Course participants willprepare a written dissertation and will beexpected to orally defend tleir work. r

ICTP VisitingMathematician wins Max-Planck ReSearch Award

Dr. Ma Zhi-Ming, Visitinglvlathematician at ICTP frorh the ChineseAcademy of Sciences, Beijing, P.R.China, has been elected recipient of theldax Planck Research Award togettrerwith Prof. Sergio Albeverio, fromUniversity of Bochum, Germany, andProf. Michael Rdckner, from Universityof Bonn, Germany.

The award has been granted to Prof.Ma ZhiMing and Prof. Albeverio inrecognition of their pastaccomplishments in research. TheAward amounts to DM 100,000 and isprovided for research work incollaboration with Prof. Albeverio overaperiod of three years.

The awarding ceremony was held inBonn at the Alexander von HumboldtFoundation on 8 December. a

Collaboration inMathematics

The Mathematics Research Group ofICTP has started a programme of jointseminars and discussions of openproblems, in collaboration with theScuola Normale Superiore (Pisa, Italy),the International School for AdvancedStudies (SISSA) and the University ofTrieste. a

The Diplorna Course participants of High Energy Physics, Condensed Maner Physics andMathernatics with Professor Abdw Salarn, Director ICTP and President TWAS.

5


Atoms inIntense Laser Fields

Concepts of multiplntons processesinvolving radiative-elecffon scattering,above-threshold ionisation and multi-harmonic radiation in intense laser fieldsare briefly discussed.

F.HM. FaisalGuest Scientist, ICTP

Courtesy of Asia-Pacific Physics News,Vol. 4, Decernber 1989.

IntroductionInterest in both experimental and

theoretical studies of photon-atominteractions in intense laser fields hasincreased rapidly in recent. years. InTable 1, some properties of laser light arecompared with those of an ordinarylamp. It is at once clear from a glance atthis table that the field of a laser is veryunlike that of ordinary light in manyrespects. The recent upsurge of inlerestin laser-atom interaction is motivatedboth by the desire to understand thephysics of atoms subjected to suchextraordinary perturbations as well as bythe prospect of potential applications,e.g. in generating new kinds of radiation,laser-plasma fusion, control of chemicalreactions, generation, transmission andguidance of information at optical speedand otherproblems in photonics. HereIshall restrict myself to dre considerationof some processes of current interest inthe physics of laser-atom interaction athigh intensities. They include processessuch as multiphoton and above thresholdionisations, radiative electron scatteringand multi-harmonic seneration ofradiation.

Multiphoton ionisationOur understanding of ttre elementary

process of photo-ionisation of atoms hasgone through a significant change inrecent years. It is known for some timenow that photo-ionisation of electronsbound in isolated atom or in solids cantakeplace in the presence of light weaveswith photons of energy smnller ttran thatof the ionisation energy (or the workfunction). This is in apparent defiance ofthe traditional text book interpretation of

Property

Intensity !.

Spectral purity A

Coherence length A L.

Pulse duration AT.

Lamp

IO1 W/cm:

l0-6

lGcm

l 0 { sec

Laser

tO17 W/cnv

tcr-13

W a n

l0''a sec.

Table I

phooelectric effect, originally explainedby Einstein near the beginning of thecenturyl. Fig. 1 shows typicalmeasurement2 of ion-signals obtained byshining light from a Nd-laser of variousmodes (with h (D= l .l7 eV) on Xe-atoms.

Figure 1.Log-log plot of the variation of the

number of Xe-ions produced as a function ofthe average laser intensity (NdJaser). Thelaser operates in (a) a single-mode, (b) rwo-modes (c) seven modes and (d) phase-lockedseven modes. (From G. Mainfray, ref. 2).

The ion-signal is shown here as afunction of the light intensity, in a log-logscale. Recalling that the ionisationenergy gap of Xe-atoms is about 12.1 eVit is at once clear that photons from a Nd-laser have energy which lie below that ofthe ionisation threshold and in factconstitute only a small fraction of thelatter. How does the laser light of sub-

threshold photon energy cause ionisationof atoms? The physical picture that hasemerged from extensive experimentaland theoretical studies of these processescan be made intuitively clear with thehelp of the concept of "virtualabsorption". A virtual absorption is aprocess in which an electron in an initialbound state of energy, 8,, absorbs aphoton of (sub-threshold) energy, 6ar,and reaches a "virtual state" at an energyE. + h a (which, in general, does notcoincide with any of the eigenenergies ofthe stationary states of the system) whereit lives for a very short time. The "life-time" of a virtual state may be estimatedby the uncertainty relation and is of theorderof t=AIM, where AE is theenergydifference between that of the virtualstate and the nearest stationary ("real")state of the atom. Fig. 2 depicts this in aschematic way. The more generalphotoelectric effect by subthresholdphotons, is understood to occur bysuccessive virtual-absorptions of asmany photons as necesszfy to overcomethe ionisation energy gap.

Naturally, such processes will haveonly a negligible probability in the fieldsof ordinary light; due to their weakintensity, they cannot provide sufficientphoton-density for the successiveabsorptions to takeplace within the short(-10'tu sec.) "life-time" of the virtualstates. The actual probabilities of suchprocesses can be calculated usingappropriately higher order perturbationtheory (see e.g. ref. 3, chapter 2). Thebasic result of perturbation analyses canbe summarised by the now well-knownpower law: WN)-FN) where WN) is the rateof the multi-photon ionisation requiringabsorption of N-photons. It is dhecrlyproportional to the M' power of theintensity I. (I = Eo2clSn = n,ha)clL3,where E, is the classical peak amplitudeof the laser-field, (nolL3) is the quantalnumber density of photons and c is the


3

•mh

o•si

H

o

0 - 5

I }

e Ground srarc

Figure 2.A schematic illusnating the position of a

"virtual state" (denoted by the dash-dot line)in a level-diagramme and its "life-time" -r=$IAE. AE is the distance to the nearesrstationary (or "real") state. The wavefunction of a virtual state is a linearsuperposition of all the stationary states of thesystem, which appear with decreasingrelative strength with increasing distancefrom 0re virtual state.

velocity of light).Fig. I is typical of multi-photon

ionisation signalatlowerintensities. Theinitial linear dependence of theexperimental result with either singlemode or many mode lasers confirms thislaw. The power law is essentiallyindependent of the kind of atoms used inexperiments. A characteristic intensity,{ , of the atomic system is the intensity ofthe Coulomb field of t le nucleus ofatomic hydrogen experienced by anelecfron in its ground state and i s / = 3.5Ix 1016flcm2. Thus, fork</ " the powerlaw may be expected to yield a rapiddecrease of the multi-photon ionisationsignal with increasing N (decreasingapproximately by a factor of the order of(///o) for every increase of N by one).

Multi-harmonic radiationOne of the more interesting effects

currently under investigation, is thephenomenon of the multi-harmonicradiationa,5'6. This process ischaracterised by emission of a wholespectrum of harmonic photons when astrong laser-field of a fixed photonenergy is allowed to interact with atomsat high density. For example, tle multi-

harmonic radiation (MIR) spectrumcontaining all the odd harmonics as far asthe 33rd harmonic has been observed,when noble gas atoms were made tointeract with snong Nd-laser fields. Fig.3 shows such a MHR-spectrum obtainedby shining Nd-laser of intensity -1013Wcm2 on Ar-atomss.

3 7 35

Figure 3.A mu lti -harmonic radiation spectrum,

Relative intensity of multi-harmonicsgenerated by Ar-atoms in Nd-laser field (fi co= 1.17 eV, I o 3 x 10" W/cm2). The 13thharmonic is absent apparently due to strongabsorption of 91.9 nm radiation by photo-excitation of a 5d-state. (From M. Fenay etal.,ref.5).

From quantum mechanical point ofview this implies creation of newphotonsby fusion of several (or many) laserphotons from the incident field. Such"fusions of photons" in multi-harmonicradiation can be viewed to occur asfollows. The incident phoons of energy•fi w force the active electron to be excitedtemporarily to a state of energy nhmabove tlte ground state (by stimulated n-photon absorption). This state of ttreelectron can be in general a virtual one ifnfal is below the ionisation threshold orit can be a real state in the continuum.The excitation energy nfia is thentransfered to a vacuum mode of energyf>Q = nfia , with a probability whichbecomes generally appreciable only athigh incident photon-density. A newphoon of energy rt(Z = nrto is thencreated as the active elecfron returns tothe initial (ground) state. Furthermore, in

the direction of propagation of theincident photons the amplitudes ofemission of the new photon fromdifferent atoms add up coherently, givingalV dependence of the emitted intensity,where N is the number density of atomswithin the coherence length (of the orderof the wave-length of the emittedradiation). This also explains the factwhy multi-harmonic radiation could beseen copiously in the laboralory for thefirst time when the density of atoms israised to -101 6/cm3, far above the densityusually employed (-1012/cm3l in ATIexperiments with comparable fieldintensities. Due to parity conservation inelectromagnetic interaction and centro-symmetric nature of the atomic system,multiple fusions of photons occur only inodd-harmonics of the incident photons,sothatA(2=nfrrowithn = 3,5,7,9... Dueto the magnetic quantum numberselection rule in multiphoton transitions(see e.g. ref. 3, sec. 5.2), for circularlypolarised incident photons of specifichandedness no such harmonic radiationis allowed. The origins of the mulri-harmonic radiation under condition ofuniform gas density over extendedvolume and with narrow gas jets are sofar incompletely understood. However,these and the major spectralcharacteristics of the MHR-radiationsuch as the existence of abroad plateau inthe spectral region extending from the9th harmonic toa very high harmonic anda subsequent relatively abrupt cut-off,the unusual laser intensity dependence,its connection with the conespondingspectra of A'fl and related problems arecurrently being studied vigorously6' 7'8.This phenomenon opens up thepossibility of efficient generarion ofcoherent soft X-ray photons by directinteraction of low-frequency laserphotons in atomic gases.

References1 A. Einstein, Ann. Phys. 17 132

(1905); 20 r99 (1906).2 G. Mainfray in Multiphoton

Processes, eds. J.H. Eberly and P.Lambropoulos, p. 253 (John Wiley,rvY 1978).

3 F.H.M. Faisal, Theory ofMultiphoton Processes (PlenumPress, New York, 1987).

cortinued on Page 8


Primo Rovis Prize 1992

The Committee of the InternationalPrize "Primo Rovis" selected theNepalese joumalist Peakash Khanal aswinner of the Prize this year, for hisactivities aimed at disseminatingscientific culture. He was handed thePrize by Mr. Primo Rovis himself in thepresence of the Director of ICTPProfessor Abdus Salam on 18December.The Prize, instituted out of the generosityof businessman Primo Rovis, and withUS$ 20,000, is a token of the role whichTrieste isplaying in Italy and the world inthe field of scientific culture. The PrizeCommittee, presided over by Prof.Abdus Salam, Director of ICTP, iscomposed of representatives ofinternational repute from localuniversities and research institutes. Mr.Peakash Khanal is the in-chargeof publicrelations at the Royal Academy ofSciences and Technology of Nepal,directs a scientific journal, and iscorrespondent from Europe for South-East Asian countries. 0

cortinued from Page 7

* A. McPherson, G. Gibson, H. Jara, U.Johann, T.S. Luk, I. Mclntyre, K.Boyer and C.K. Rhodes, J. Opt. Soc.Am. 84, 595 (1987).

5 M. Ferray, A. L'Huillier, X.F. Li,L.A. Lompr6, G. Mainfray and C.Manus, J. Phys. B2l, L3l (1988).

6 K.C. Kulander and B.W. Shore,Phys. Rev. Lett. 62 524 (t989).

7 J.H. Eberly, Q. Su and J. Javanainen,Phys. Rev. r.ett. 62, 881 (1989).

8 F.H.M. Faisal, in Atons in StrongFields, ed. C.A. Nicolaides @lenumFress, New York, 1989).

From left to right: Mr. Pealeash Kluna| Mr. Primo Rovis and Professor Abdus Salarn.

lnterview with Peakash Khanalby A.M. H amendc

Third World Academy of Sciences

Mr. Peakash Khanal, a journalistfrom Nepal, received the medal of theTrieste International Foundation for theScientific Progress and Freedom on 14December 1992, n recognition of hisoutstanding work in the popularization ofscience. Professor Abdus Salam is thePresident of the Foundation.

Q.: Mr. Khanal, let me first of allcongratulate you on the medal presentedto you by the Trieste InternationalFoundation for the Scientific Progressand Freedom. Can you tell us how youcame to know about the Foundation andthe intemational institutions in Trieste?

A.: It is indeed a great honour for meto receive the "Primo Rovis" Medal fromthe Trieste International Foundation forthe Scientific Progress and Freedom. Imust say that I never anticipated medalsand awards when I started to popularizescience as a journalist. But I must confessthat this recognition of my services to thisfield has greatly motivated me and hasgiven me a cause and enhanced myresponsibility for continuing !o serve thisneglected domain from which a largersegment of our society stands to benefit.

IhaveknownofTWASandICTPfor

many years because of my associationwith the Royal Nepal Academy ofScience and Technology (RONAST). Ihad the first oppornrnity to work closelywith TWAS and ICTP in 1989 when theFirst Summer School of Physics wasorganized in Kathmandu. ThroughTWAS and ICTP information channels Ilearnt about the Foundation for ScientificProgress and Freedom and ttre himoRovis Award.

Q.: The Third World Academy ofSciences considers that thepopularization of science through mediais very important for raising the level ofscientific culture in the developingcountries, particularly at the grassroot.You have written many articles for thepress of your country. Do you think thatthey can influence ttre public opin ion andthe viewpoint of decision makers inNepal?

A.: Like TWAS, RONAST whichwas established in 1982, recognized theneed to raise thelevel of scientific culturein Nepal. Great priority was given to theestablishment of an information networkand to stafiing scientific awarenessactivities. As a result, a pilot science


popularization project with financialsupport from the InternationalDevelopment Research Centre (IDRC),Canada, was launched in 1985 under theaegis of RONAST. Therefore, 1985 wasthe first year of the sciencecommunication and science journalismera in Nepal.

I have written numerous articles forthe Nepalese people as well as for theforeign press outside Nepal. I have editedthe first science feature produced in mycountry for the exclusive use of massmedia in Nepal. But it is extremelydifficult to say whether those articles hadany influence on the readers andlisteners. However, one thing is sure:these articles were read by many andsome of the information contained inthem was useful. This was conveyed tome through various channels. Forexample, after the publication of a pieceon the possibility of corneal transplantand its relationship with eye donation, Ireceived many letters requesting moreinformation about the subject andexpressing willingness or the readers todonate their eyes after their death. Thiswas also confirmed by the Eye Bankauthorities.

Q.: You work for the Royal NepalAcademy of Science and Technology.Can you think of any help from the ThirdWorld Academy of Sciences to assist youand your colleagues, in the disseminationof scientific information?

A.: Scientific information is a seriousissue and there shouldbe much more thansingle pilot projects. For example, thereshould be training institutions or at leastscience journalism training programmesas well as continuing centres forinformaleducation and learning for the promotionof scientific awareness and forstimulating science and environmentpopularization activities. TWAS couldprovide support with funds and withscholarships to train more sciencejoumalists or science copmunicatorswho will take up ttris challenging task.Perhaps, more awards need to be createdto motivate more people to go into this

continued on Page 1I

Second UN/ESA Workshop on Basic Space Science

Hans J. HauboldUnited Nations, New York.

Second Uniled Natians (UN)lEuropean Space Agency (ESA)lThe PlanetnrySociety (TPS) Workshop on Basic Space Science, held at the University of Costa Rica,San Josd(CostaRica),2 to7 November 1992, andat the Universiry ofthe Andes, SantaFe de Bogotd (Colombia), 9 to 13November 1992.

The United Nations Office for OuterSpace promotes collaboration in spacescience and technology amongindustrialized and developing countries.This workshop has been organized aspart of the United Nations Programme onSpace Applications, observing also theInternationalSpaceYear(ISY) 1992 asaworld-wide initiative of space agenciesand the scientific community to enhanceinaernational collaboration in the field ofbasic space science. The workshop (i)brought together asEonomers from 13countries of Latin America and theCaribbean, Canada, Germany, Sweden,United Kingdom, United States ofAmerica, ESA, NASA and the UN, (ii)addressed scientific issues in planetaryand solar system science in Costa Rica,cosmology and astronomy spacemissions in Colombia, and (iii) madeobservations and recommendations forpromoting basic space science,particularly in latin America and theCaribbean. The objectives of theworkshop were achieved throughintensive mutual discussion and detailedpresentations made by selectedastronomers from countries referredabove. The workshop was held in thespirit of the continuing quest forfundamental knowledge, turning theachieved knowledge into educationcurricula, and the search for internationalcollaboration at the highest scientificlevel. The ESA lecture (W: Wamsteker)"Archives and their relation to thedevelopment of fundamental scientificideas", the TPS lecture (CR. Chapman)"Catastrophic impacts on Earth", the ISYlecture (R. v. Ammon) "Detection ofastrophysical neutrinos", and thepresentations made by W. Fernandez(Costa Rica) "Changes in solar

irradiance and atmosphere torbidity inCosta Rica during the total solar eclipseof July 1991." and S. Torres (Colombia)"COBE results and their cosmologicalimplications" were setting the frame ofthe scientific programme of theworkshop. Among the distinguishedspeakers whose support for the workshopwas exemplzry were W.J. Anderson(Canada), J. Bennett (NASA), C.G.Faelthammar (Sweden), M.H. Ibanez(Venezuela), A.M. Mathai (Canada), J.Sahade (Argentina) and H.U.Zimmermann (Germany). Through theinitiative of Prof. M. Kitamura (Japan)the government of Japan will continue tosupport the establishment of nationalastronomical observatories indeveloping countries through theprovision of equipment for astronomicalresearch telescopes. The EuropeanSpace Agency intends to providecomputer systems to research institutesand universities in developing countries.In the futue the United Nations Officefor Outer Space will take itsresponsibility in promoting this series ofworkshops and internationalcollaboration in the field of basic spacescience. After organizing workshops inAsia (India) and Latin America and ttreCaribbean (Costa Rica and Colombia)the activity will be canied on to Africa.The philosophy of organizing thisworkshop will remain to bring togettreractive astronomers from developing andindustrialized countries and to seekstrong support from space agencies andthe intemational scientific community tostrengthen the growth of basic spacescrence rn countnes where this science inall its aspects has not yet been fullyd e v e l o p e d . I •

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Brian David fosephson (U.K.), 1973"for his theoretical prediction of the

properties of a super-current through atunnel barrier, and in particular thosepherwmetu which are gerwrally known aslosephson effects".Dates of visits:1972, September 18-251973, August.

Thirty-five Nobel Laureateshave visited the ICTPsince 1964.The citations for the Prizeand detes of their visitsare given for five of themin this issue.More will be publishedin future ICTP newsletters.

Samuel Chao Chung Ting (U.SA.), 1976"for the discovery of a new rype of elementary

particle Latown aspsi".Dates of visits:1970, September 15 -I81974, June 19-231989, October 3l -November 3.

Subrahmanyan Chandrasekhar (India),1983"for his studies of tlw physical processes ofimportarrce to tlle structure and evolution ofstais".Date of visit :1975, July 9 =13.

Chen Ning Yang (U.SA.), 1957"for perutrating iwestigations of the paritylaws which led to important discoveriesregarding subatomic particles".Date of visit:1981, December 12-15.

Burton Richter(U.S.A.), 1976"for the discovery of a n"ew type of elementaryparticle known aspsi".Dates of visits:1974, Jure 19-221987, June 29 -August 7.

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Role of Science in Indian Societv

SN. TiwaryAssociate, ICTP.

The first Prime Minister of India,Pandit Jawaharlal Nehru, formulated thescience policy based on the fact that ourproblems of hunger, poverty andpopulation can be solved only by science.Science cannot remain confined to theivory towers of the universities andresearch institutes. Scientists have toeducate the society in such way that atevery level there should be a scientificattitude and an aptitude to understand thenature of scientific knowledge and theprocess of the investigation thatgenerates knowledge.

Bertrand Russell rightly said, ..Asociety can be called scientific in thedegree to which scientific knowledge,and the techniques based upon that,affects its daily life, its economic and itspolitical organizations". To what extentis the Indian society scientific in theabove sense? No doubt the Constitutiongrants us freedom of speech, but theIndians do not enjoy the freedom fromwant of food and water, from fear ofdiseases, torture and terrorism.

In a fit of frustration one may say thatthe average happiness in the societytoday is much less than before the adventof scientific revolution. But science cannot be blamed for this. It provides ameans which can be used or misused.Science has brought to us enormousmaterial advantages, but the scientistshave failed to see that they are properlyhandled and uniformly distributed.

However, one can not fail to observethat science has improved the quality oflife in the world and in India. Science isaiming ata smaller, con tented populationwith abler and more productive handsand fewer mouths to be fed, so that thenation can progress to economicprosperity.

Science has contributed immenselyto industrial and agricultural growth, sothat there is restricted import andincreasing export. The nation couldsurvive the worldwide economic crisisand is progressing to recovery. Sciencehas always come to the rescue of thenation and it has not failed our country.

Semiconductors, microchips andcomputers helped the industriesimmensely. The introduction ofsuperconductors is on the anvil.Transportation, communication, labourand management have become efficient.Availability of energy has improved. Inagriculture, the use of better quality ofseeds, fertilizers, pesticides and betterirrigation facilities has brought greenrevolution. Better breeding methodshave brought boom in poultry, meat, fishand dairy products.

Our natural resources have beenexplored. Fields and ocean beds arebeing tapped for natural oil, leading topetrochemical industries. Alkaliindustries have developed based onmarine chemicals. Numerous drugs andimproved surgical methods haveeradicated various diseases and made lifehappier. Family planning devices areshowing results.

There are some arguments that theother worldly attitude in the Indianphilosophy hinders the growth ofscientific temper in the society.Scientific theories and moral truths arecomplementary to each other.Contradiction between Indianphilosophy and science does not existany more. Let the Indian society beimbued with the spirit of science.Planned use of science will certainlymake the nation economically advancedto attain geater prosperity. Only sciencecan save fte nation. . o •

Interview with Peal<ash Khawl.couinued from Page 9

profession. The awards do not need to beof a huge amounc a medal and a visit toscientihc institutions will be useful.

Q.: You have visited the scientificinstitutions in Trieste. What are yourimpressions? Will you write about them?

A.: Trieste is the first science city Ihave visited and itgave mean impressionof how a real science city should looklike, bursting with national andinternational centres of scientificexcellence. Upon reaching here l realizedthat ICTP/TWAS and the untiringpersonality of Nobel Laureate prof.Abdus Salam have not only become asource of inspiration to many talentedscientists from the developing world whowithout these institutions would haveended in oblivion, but has also played anequally important role within Italy. Thistranspires from the internationalinstitutions and from the research anddevelopment centres ttrat have come tobe created within Italy. It is veryimpressive to see that Trieste has carveda very special place. Its fame is bound tomultiply with the scientificachievements in the coming years.

Born in October 1958, peakashKhanal obtainedaB.Sc. atthe TribhuvanUniversity in Nepal in I98I and ispresently completing a Master inBusiness Administration at the sameuniversiry. He currently works at theRoyal Academy of Sciences andTechnology where he is in charge of theliaison with the media. He has writtenmany articles on science andenvironment for newspapers andjournals qnd contibutes to radio andtelevision programmes production. He isalso the coordinator of a course forprospective journalists and a consultantfor science and technology promotionand popularization. o

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Obituaries

Prof. A. Borsellino

Prof. A. Borsellino, a distingushedbiophysicist of Italy, died attheageof 77.Born in Reggio Calabria (taly) in 1915,he obtained his degree in physics in 1938at ttre Scuola Normale Superiore in Pisaand started immediately researchactivities at the Polytechnic of Milanwhere he aught until 1950 when hebecame Full Professor in theoreticalphysics.

In the '50s, when the description ofelementary processes ofelectromagnetism was topical, Prof.Borsellino became notable forexamining for the first time the processwhereby a photon produces an electron-positron in an electron field. He was theauthor of an important research on the so-called electromagnetic showersproduced by cosmic rays. Hans Bethe,Nobel Laureate 1967, remarked thefundamental role of ProfessorBorsellino's research. To beremembered are also his studies onnonclassical statistical laws to whichelementary particles are subjected aswell as those on photonuclear reactions.

At the University of Genoa he was aninnovator who took the fame of thedepartment to an intemational level. Heinsisted for introducing computers at thatuniversity which then could boast one ofthe first computer centres in ltaly.

In the mid '60s Prof. Borsellinobecame interested in biophysics andneurophysiology as he was convincedthat mathematical and experimentalmethods could be applied to those fields.Thus, he became one the fathers ofbiophysics in Italy — he founded theLaboratory of Cybernetics andBiophysics of the National ResearchCouncil and developed a school in Genoawhich has produced very good resultsand scholars.

In 1985 he moved to Trieste wherethe International School for AdvancedStudies (SISSA) requested him to srarrand develop a research group inbiophysics. •

Prof. R. Marshak

Professor Robert E. Marshak, anoutstanding physicist and a scientist ofworld renown, died on 23 December1992. Prof. Marshak, 76, led CityCollege of New York, USA, during the1970s and later was a Professor atVirginia Polytechnic Institute and StateUniversity in Blacksburgh. He drownedin the sea on December 23 while onvacation in Cancun, Mexico.

Prof. Marshak, a distinguishedProfessor Emeritus of physics at VirginiaTech. and State University, had recentlybeen selected as fte first recipient of anAmerican Association for theAdvancement of Science Prize forfostering international scientificcooperation. Most of his career wasspent at the University of Rochester inNew York where he was Chairman of theDepartment of Physics andAstrophysics.

He was a great friend of ProfessorAbdus Salam, Director of theInternational Centre for TheoreticalPhysics, Trieste, Italy. In 1960 hediscussed with Prof. Abdus Salam thefeasibility of an international centre fortheoretical physics. He became amember of Three Wise Men FeasibilityStudy Committee of the InternationalCentre for Theoretical Physics (ICTP),Trieste, Italy. In 1967-75 he was aMember of Scientific Council of theInternational Centre for TheoreticalPhysics (ICTP), Trieste, Italy.

He wrote a number of books aloneand in collaboration including a book tobe published as a textbook "TheConceptual Foundation of ModernParticle Physics". •

Activities at ICTPin November-December

T i t l e : S E C O N D A U T U M N W O N R S H O P O N

MATHEMATICAL E c o L o c Y , 2 - 2 0

November.Organizers: Professors L.J. Gross

(University of Tennessee, Knoxville,USA), T.G. Hallam (University ofTennessee, Knoxville, USA), S. A. Levin(Princeton University, USA) and G.Vidossich (International School forAdvanced Studies, SISSA, Trieste,Italy).

Lectures: Water quality andgovernmental regulation issues. Riskassessment measures in conservationbiology. Modelling water-sedimentinteractions. Individual-basedapproaches in ecological riskassessment. Conceptual issues inbiological diversity. Computer-basedrisk assessment tools. Low and highfrequency oscillations in threedimensional food chain systems.Decision theory and extinction risk. Therole of the biosphere in climate change —questions and rationales. Africanelephants and the ivory trade: theimportance of social structure indetermining population viability. Usingall the data: modern approaches tointerpreting fisheries data. The problemof scale. Global climatb modelling.Biospheric components of earth systemmodels with emphasis on soils processes.Landscape-scale models. Competitionand cooperation in a marine fishery:applying ecological principals in abioeconomic analysis. Populationmodelling: the zebra mussel in NorthAmerica. Tick population modelling atthe ICIPE. Computer-informationalsyslem bank of ecophysiological plantmodels. A three age-groups model forHIV-AIDS epidemic (in Uganda).Rocket scientists have it easy. Infectiousdiseases and conservation biology:rinderspest in the Serengeti andbrucellosis in Yellowstone. Modellingresponse functions and data analysis.Distributed lags in discrete dynamical

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systems. Island biogeography revisited.The growth model of H. persicumpopulation in Mosouwan Desert ofZhungeer Basin. Models for animalmovement of a home range. Persistenceand evolutionary dynamics influctuating, spatially structuredpopulations. An inroduction to AIDSmodelling. Thermodynamic ideas inecology. Epidemic modelling. Softwarefor teaching and doing research inecology. The threshold betweenpersistence and extinction of populationsinvaded by toxicant and some openproblems. Risk analysis in agricultwe.Structured dynamical models of foreststand dynamics in different time scales.A unified approach to model socialdynamics and pair formation withapplications to epidemiology. Modelsfor wildlife: individual-based tolandscape approaches. Simulationmodelling system for aquatic bodies.Global climatic changes and someconsequences for Russia. Resource

management based on risk analysis.Dynamical systems in biology:Lyapunov functions and information.Chance and chaos in measles dynamics.Nanral selection in a diploid host and isviral pathogen. A new strategy forpreventing measles epidemics. R0 formodels of sexually fansmitted diseasesthat take long lasting parher relationsinto account. Discrete effects incontinuous ecological models. Methodsfor estimating mixing/pair formationmatrices. Plant life history theory andpopulation dynamics. The cumulativeformulation of structured populationdynamics. The saturating contact rate formarriage and epidemic models.Environmental variation and speciesrichness: a model and an example.Stability problems in chemostatequations with delayed nutrientrecycling. A qualitative analysis ofchemos[at equations with (or without)delay nutient recycling. Models in plantbiology: from physiology to landscape

scale. Simulation models for riskmanagement. SAbility and persistence inmodels with dispersion. Naturalselection and the dynamic coexistence ofdefective and complementing virussegments. Energy partitioning modelsand conservation practice. Seasonalcomponents of transmission in a free-living host-parasite system. Fishpopulations in flooded regions. Life spanof irradiated mammals — mathematicalmodelling. Bifurcative analysis ofpredator-prey population models. Doplants adopt optimal reproductivestrategies? Models of Chagas' disease.Desertification, causes and possiblesolutions. Disturbance and the dvnamicsof tropical forests.

Working Groups:Conservation biology assessment:

RAMAS - model demonstration.Applications of RAMAS.Environmental data from aquaticsystems in Italy. Decision theory andextinction risk.

Second Autunm Worlcshop on mdhernatical ecology, 2-20 Novernber.

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Worlcshop on three-dinlcnsional modelling of seismic waves generation, propagation and their inversion, 30 November -II December.

Ecological risk ossessment:Computer tools. Ecological models.

Resource menagement: TheSerengeti ecosystem: developing simplemodels for analysis of resourcemanagement alternatives in an AfricanPark.

Global change.Epidemiology.Forestl agriculture.

The Workshop w:rs attended by 98lecturers and participants (57 fromdeveloping countries).

Title: WONXSNOP ON RHREE-

DIMENSIONAL MODELLING OF SEISMIC WA\IES

GENERATION, PROPAGATION AND THEIR

RR{VERSRON, 30 November -11 December.

Organizers : Professors B.G.Bukchin (International Institute ofEarthquake Prediction Theory andMathematical Geophysics, RussianAcademy of Sciences, Moscow, Russia)and G.F. Panza (University of Trieste,Italy), in collaboration with rhe

International Centre for Science andHigh Technology (ICS, Trieste, Italy)and the Institute of Geodesy andGeophysics of the University of Trieste.

Lectures: Lg Coda Q ameasurement and physical significance.A back-projection technique forLg CodaQ tomography. Introduction to computerexercises. Seismic source models.Implications of Lg Coda Q for crustalstructure and evolution. The inverseproblem for the seismic source. Syntheticseismograms calculations in lD and 2Dmedia from multimodal summation.Seismic ray method for 3-D structures:possibilities and limitations. Finiteintegral transformations of differentkinds and ttreir use in the forward seismicproblems. New frontiers for worldsafety. Some problems of seismictomography. The spectral-finitedifference method for the forwardseismic problems for a verticallyinhomogeneous half-space and radially-inhomogeneous sphere. Determinationof spatio-temporal characteristics of a

seismic source from surface wavesamplitude spectra. Frequency-timeanalysis. The spectral finite differencemethod for the calculation of syntheticseismograms for 2D and 3D models ofmedia. Reconstruction of tectonic sftessfield from seismic observations.Charactsrization of strong motion andwave propagation based on s mart-1 data— source and local effects. Numericalinvestigations of non-ray waves. Themethod for geophysical explorationbased on the interaction of seismic waveswith the Earth's magnetic field. Groundmotion modelling for seismic hazwdzoning. Synthetic seismograms with ahybrid method: coupling of modesummation and finite differences.

Computer exercises.

The Workhop was attended by 63lecturers and participants (35 fromdeveloping c o u n t r i e s ) . _ o

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Calendar of Activities at ICTPL993

Sixth International Workshop on computational condensed matter p h y s i c s . . . . 1 1 - 13 January

Experimental Workshop on high temperature superconductors and related materials

(advanced activities), San Carlos de Bariloche, Argentina II - 29 January

Fourth Training College on physics and technology of lasers and optical fibres 18 January - 5 February

Second Workshop on functional-analytic methods in complex analysis

and applications to partial differential equations , 25 - 29 January

Third ICTP-URSI College on theoretical and experimental radiopropagation p h y s i c s . . . . . . . . 1 - 26 February

Winter college on optics ...8 - 26 February

Workshop on scientific aspects of the rural communications in developing c o u n t r i e s . . . . . . . . . . . . . . . . . 1 - 5 March

Adriatico Research Conference on quantum interferoraetry 2 - 5 March

Conference on "Highlights of particle and condensed matter physics" 8 - 12 March

Workshop on representation theory of Lie groups 15 March - 2 April

Spring School and Workshop on string theory, gauge theory and quantum g r a v i t y . . . . . . . . . . . . . . . . . . 1 9 - 29 April

Meeting on "Intracellular channels, organelles and cell function" 21 - 23 April

Sixth Workshop on perspectives in nuclear physics at intermediate e n e r g i e s . . . . . . . . . . . . . 3 - 7 May

Workshop on qualitative aspects and applications of nonlinear evolution e q u a t i o n s . . . . . . . . . . . . . . . . . . . . 3 -14 May

Course on ocean-atmosphere interactions in the Tropics 10 - 29 May

College on computational physics 17 May - 11 June

Spring College on plasma physics 17 May - 11 June

Summer School in high energy physics and cosmology 14 June - 30 July

including

Third School on non-accelerator particle astrophysics 28 June - 9 July

Miniworkshop on strongly correlated electron systems 21 June - 9 July

Research Workshop in condensed matter, atomic and molecular p h y s i c s . . . . . . . . . . . . . . . . . . 2 1 June - 3 September

Adriatico Research Conference on strong correlation phenomena at low carrier d e n s i t i e s . . . . . . . 2 2 - 2 5 June

Adriatico Research Conference on scattering from surfaces 6 - 9 July

l5


Workshop on the liquid state of matter: opportunities from new radiation s o u r c e s . . . . . . . . . . . . . . . . . . . . 1 9 - 3 0 July

Miniworkshop on non-linearity: chaos in mesoscopic systems 26 July - 6 August

Adriatico Research Conference on mesoscopic systems and chaos, a novel a p p r o a c h . . . . . . . . . . . . . . . 3 - 6 August

Conference on variational problems in differential geometry and partial differential equations 16-20 August

Adriatico Research Conference on vortex fluctuations in high T. s u p e r c o n d u c t o r s . . . . . . . . . . , , , , , , 1 7 - 2 0 August

Working Party on mechanical properties of interfaces 23 August - 3 September

Workshop on materials science and physics of non-conventional energy sources 30 August - 17 September

Course on geometric phases 6 - 17 September

College on soil physics 6 - 24 September

Second Workshop on composite media and homogenization 20 September - 1 October

Workshop on telematics 27 September - 22 October

Workshop on radioecology: mechanisms of transfer of radionuclides to the environment 1L-29 October

Conference on the origin of life 25 - 29 October

Second School on the use of synchrotron radiation in science and technology:

"John Fuggle Memorial" 25 October - 19 November

Trieste Conference in high energy physics 8 - 12 November

Second Workshop on non-linear dynamics and earthquake prediction...................,.............22 November -10 December

IcTP-uNu-Microprocessor Laboratory: Third Course

on basic VLSI design techniques 22 November -17 December

For information and applications to courses, kindly write to the Scientific Programme Office.

Intemational Centre for Theoretical Phvsicsof IAEA and UNESCOStrada Costiera, 11P.O. Box 58634014 TriesteItaly

Telephone: (40)22401Cable: CENTRATOMTeler 460392 ICTP ITelefax: (40)224163

E-mail: [email protected]: POSTOFF@ITSICTP

Decnet: VXICPI::POSTOFFICEor 38436: :POSTOFFICEPPSDN: 022224110125

EDITORIAL NOTE - News from ICTP is not an official document of ttre International Centre for Theoretical Physics. Its purpose is to keepscientists informed on past and future activities at the Centre and initiatives in their home cormtries. Suggestions and criticisms should be addressedto Dr. M. Farooque, Scientific Information Officer.

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international centre for theoretical phvsics · giambiagi said, "i have the honour to confer...

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