projects available in 2018 - the university of sydney available in 2018 ... honours students are...

Projects available in 2018 A short description of the work carried out by the different Research Groups is now given, followed by a listing of project titles, supervisor contact details and a paragraph describing each of the projects. The titles represent only some of the opportunities available for research projects and you are welcome to explore other possibilities in your field of interest with potential supervisors in the School of Physics. It is very important to choose a project and supervisor to suit your interests and skills. You are strongly encouraged to have discussions with several possible supervisors before making a decision. Speaking to current Honours and postgraduate students will also give you valuable feedback. The Web of Science, accessible from the Library website, will give you information on the research activity of the School's academics. You should also read the Research pages on the School's website (http://sydney.edu.au/science/physics/ ) for more information on the different areas that are currently being researched. Students should decide upon projects as early as possible, and must arrange a supervisor and project prior to applying for Honours. You should aim to start 3 weeks before the start of lectures. This will enable you to get your project under way before lectures and assignments compete for your time. Students should make certain that their proposed supervisor will not be absent for protracted periods during semester, unless an associate supervisor is also involved. These issues will need to be formally settled when you submit your Research Plan, two weeks after the start of your first Semester as an Honours student. Honours students are expected to continue working in their Research Groups during the normal undergraduate vacation periods, except for the designated rest period for students commencing in the July Semester (see Important Dates section). Overview of Research Themes The School of Physics is large and diverse, and offers a broader range of research areas in Physics than any other university in Australia. Research in the School is often presented in terms of Research Themes, listed below: Research Projects in Astronomical and Space Physics2 Research Projects in Atomic Molecular and Plasma Physics16

Research Projects in Biological, Biomedical and Medical Physics19

Research Projects in Complex Systems29

Research Projects in Nanoscience40

Research Projects in Condensed Matter Physics42

Research Projects in Particle Physics Research Projects in Photonics and Optical Science51

Research Projects in Physics Education67

Research Projects in Quantum Physics and Quantum Information68

Theoretical Physics Group73 Details of these research activities can be found at: http://sydney.edu.au/science/physics/research/index.shtml

http://sydney.edu.au/science/physics/

http://sydney.edu.au/science/physics/current/hons_dates.shtml

http://sydney.edu.au/science/physics/research/index.shtml

Honours Project Offering 2018 v.1 2

Projects for 2018 by research themes

Research Projects in Astronomical and Space Physics

Title of Project: Suppression of star formation in massive galaxies by relativistic jets

Supervisor: Prof Scott Croom

Co-supervisor: Prof Elaine Sadler

Email Contact: [email protected] Brief Description of Project or Project Area:

Almost all galaxies contain super-massive black holes (a million to a billion times as massive as the Sun) at their centres. The most massive galaxies are found to contain only old stars, with little ongoing star formation. The lack of ongoing star formation is thought to be due to the heating of gas in the galaxies by relativistic jets from a super-massive black hole. These jets are clearly visible in radio frequency observations. We have built a major new survey of radio emitting jets in galaxies over a large range in cosmic time. In this project, we will use multi-band imaging to model the emission of these galaxies, at radio, infrared, optical and ultra-violet wavelengths. Using this approach, we hope to clearly quantify the amount of residual star formation in massive galaxies and directly test the radio feedback model.

Title of Project: Location, location location: where are the most active super-massive black holes?


Co-supervisor:


While most or all galaxies have super-massive black holes at their centres, only a small fraction of these are actively accreting gas, and shining brightly as active galactic nuclei (AGN). We still have a relatively poor understanding of what event in a galaxy’s life causes its black hole to start an accretion episode. Is this via internal processes, within the galaxy? Or is the accretion driven by external influences? The large-scale external environment is thought to be a major factor in disturbing galaxies and triggering the flows of gas that can be accreted onto black holes. In this project, you will use the latest major galaxy survey carried out on the Anglo-Australian Telescope, the Galaxy And Mass Assembly (GAMA) survey to find the location of active galaxies. These data will be used to answer question such as: are galaxies with active black holes more likely to be in groups with other galaxies? Are galaxies with active black holes in the centres of groups?

mailto:[email protected]



Title of Project: Setting the clock on black hole feedback


Co-supervisor:


Accretion onto super-massive black holes is thought to profoundly influence the growth of galaxies, supressing star formation. Bizarrely, it has been hard to find direct evidence of this influence in galaxies where the central super-massive black hole is accreting at its highest rate. The fundamental reason for this is that the time-scale of accretion onto black holes can be very different to the time-scale for star formation. In this project we will use multi-wavelength data on local galaxies from the recent Galaxy And Mass Assembly (GAMA) to measure the star formation rate time-scale over a range of scales from a few million years to a billion years. We will directly compare the star formation time-scales derived from galaxies with and without active black holes to measure the impact of feedback from the black holes.

Title of Project: Testing dark matter models using galaxy spins


Co-supervisor:


Dark matter remains a mystery. Although various different arguments require that the dominant mass component in the Universe is not baryonic, the specific type of matter remains unknown. The standard model currently assumed is that dark matter is a cold (non-relativistic) massive particle. However, this predicts more small-scale structure than is currently observed. An alternative is warm dark matter, which erases some of the small-scale structure. One of the usual ways to test this is to look at the number of galaxies as a function of mass. Cold dark matter predicts we should have many more low mass galaxies. The challenge is that feedback from the process of galaxy formation can also change the number of galaxies that form (or rather the number of stars that form in them). A cleaner way to carry out this test is to measure the mass of galaxies more directly, which can be done using the motions of gas and stars. In this project, we will use the rotations of galaxies from the new University of Sydney led SAMI Galaxy Survey to measure the distribution of galaxies as a function of rotational velocity and mass, and compare them to predictions of cold dark matter and alternative warm dark matter models.




Title of Project: Getting the perfect 3-D picture


Co-supervisor:

Email Contact: [email protected] Brief Description of Project or Project Area: Optimal image reconstruction is of fundamental importance in a number of fields including medicine geology and astronomy. As data sets become larger and more complex, with higher dimensionality, it is more important than ever to get the best use of the data. In this project, we will bring together some of the latest methods in image reconstruction, such as Gaussian processes, and apply them to state of the art 3-dimensional astronomical data sets (taken from the SAMI Galaxy Survey being led by the University of Sydney). We will aim to modify general techniques to take into account practical effects (such as atmospheric distortion, under-sampling and non-uniform sampling) and find optimal solutions to the image reconstruction problem. We will then measure fundamental properties of the galaxies in the reconstructed galaxy images, such as the age and heavy element content of the stars in the galaxies. This project would suit a student with some prior programing background and could be carried out in Python, Matlab or some other suitable language.

Title of Project: Precision spectroscopy of distant galaxies


Co-supervisor:


Fundamental to our ability to carry out precision spectroscopy is the need to accurately quantify the intrinsic resolution of any spectrograph. In almost all cases, particularly when targeting distant galaxies, there is an assumption of constant resolution and that the line profile provided by the spectrograph is Gaussian in nature. When we want to probe the internal dynamics of a galaxy (for example to measure the total mass, including dark matter) we often need to work near the resolution limit of spectrographs and incorrect modelling of the instrumental resolution biases our results often making it impossible to measure the mass density in the outer parts of disk galaxies. To address this problem, we need a more precise model of spectrograph resolution that is allowed to vary with both time and wavelength. In this project, the student will develop a set of new approaches to precisely defining instrumental resolution, using a range of data taken from the Sydney led SAMI Galaxy Survey. The new models of resolution will be used to provide improved measurements of galaxy dynamics and mass.




Title of Project: Planet Hunting with Large Telescopes

Supervisor: Prof Peter Tuthill

Co-supervisor: Barnaby Norris

Email Contact: [email protected]

Brief Description of Project or Project Area: The direct detection of light from exoplanets remains among the signature quests of modern astronomy, and indeed within all of contemporary science. Although indirect techniques (such as radial velocity searches) have delivered nearly 1000 planets over the last 20 years, only advanced imaging techniques able to record direct light from the planets themselves offer a pathway to future visionary telescopes able to characterize the chemistry of exoplanetary atmospheres for habitability. For this project, you will analyze (and hopefully participate in taking) data from some the world's large telescopes such as Keck, Subaru, VLT, LBT and Gemini. Advanced imaging techniques pioneered by our group have delivered the first ever detections of exoplanets at the epoch of their birth. The key aspect of the high angluar resolution images you will produce is that they reveal orbital motion, and hence masses and densities, of the exoplanets or brown dwarfs being studied.

Title of Project: The James Webb Space Telescope Interferometer




Brief Description of Project or Project Area: The James Webb Space telescope (JWST) is an $8 billion dollar space mission intended to inherent the mantle from the Hubble Space Telescope as the predominant observatory for optical/infrared astronomy into the 21st century. After its launch later this decade, the mission will deploy a 6.5m primary mirror with passive cooling out at the L2, the second Lagrangian stability point. One of the key science niches targeted by this mission is the discovery of exoplanets. For this project, you will work on a dedicated interferometer developed at the University of Sydney which will fly aboard the NIRISS instrument (we are the only Australian group to design instrumentation for this mission). The project will explore the JWST space interferometer to derive primary performance metrics, and generate a full experimental simulation of the experiment incorporating a host of real-world sources of error and imperfection. These studies will be based both on numerical simulations and results from optical testbeds in Sydney, Baltimore and Ball Aerospace (Denver). The outcome will be an optimized observational campaign for flight deployment.




Title of Project: Galactic big game: hot massive stars and supergiants




Brief Description of Project or Project Area: In the galactic eco-system, the hot massive luminous stars at the top exercise an outsize influence on the evolution of the galaxy. Exceeding our own sun by factors of five in temperature, fifty in mass, and fifty-thousand in luminosity, these T-Rex's of the stellar kingdom dominate many aspects of the physics of the galaxy, despite being outnumbered thousands to one by more normal stars. When we look at a distant galaxy, the light we see mostly comes from a handful of these overachievers, outshining the teeming multitudes of low-mass stars. For this project, you will study these rare and exotic stars with unprecedented resolution, for the first time revealing structures at the critical scale of the stellar photospheres themselves. Taking your own data with the CHARA array in Southern California, the project will be the first to separate constituents of these stellar systems for detailed study, revealing the basic physics of masses and stellar atmospheres as well as exotic mass loss processes which are critical to governing the eventual fate of these stars in Supernova explosions.

Title of Project: Astrophotonics for exoplanetary discovery




Brief Description of Project or Project Area: One of the most audacious goals in all of modern science is the discovery and characterization of extra-solar planets, and in particular, the identification of potential new worlds suited to the support of a flourishing biosphere. However, despite much progress, there remain formidable technological hurdles in the construction of any telescope truly capable of the revealing the physics and chemistry of an exoplanetary atmosphere. For this project, you will work on a revolutionary new concept, which marries recent advances in photonic control and manipulation of starlight together with leading edge new imaging technologies from astronomy such as adaptive optics and interferometry. The final goal will be the design and specification of an infrared nulling interferometer, capable of rejecting the overwhelming glare from the parent star, thereby enabling detailed study of the faint planetary light. This project can involve both instrument development and design in the new SAIL laboratories here at Physics, and/or more theoretical work in simulation and data analysis.




Title of Project: Extreme events: exploring the transient universe with the MWA

Supervisor: A/Prof Tara Murphy

Co-supervisor:


Some of the most extreme events in the Universe occur when black holes form, or merge with each other, or when stars move too close to a black hole and get sucked in. In each of these cases strong bursts of electromagnetic radiation are released, which we detect on Earth as ’transient’ radio emission. Not only are these events interesting in their own right, they also serve as an astronomical laboratory for exploring physics in extreme conditions. Until now we have had a limited ability to find and study these objects as they appear and disappear on short timescales. Radio astronomy is undergoing a revolution, with new telescopes able to conduct massive all-sky surveys on a regular basis, allowing us to discover ’transient’ radio sources. In this project, you will work with data hot off the press from the Murchison Widefield Array (MWA), a low frequency radio telescope in Western Australia. You will have access to this unique (and completely unexplored) dataset to look for transient and highly variable radio sources, and then draw on multi-wavelength data and observations from other telescopes to identify what these sources are.

Title of Project: Radio detection of gamma-ray bursts and gravitational wave events with ASKAP

Supervisor: A/Prof Tara Murphy

Co-supervisor:


Brief Description of Project or Project Area:

Gamma-ray bursts are some of the most powerful explosions in the Universe. Long gamma-ray bursts are generated when massive stars collapse to form black holes, and short gamma-ray bursts are thought to occur when two neutron stars merge and form a black hole. In both cases, radio observations of gamma-ray burst afterglows at late times give us important insights into these extreme events, and the nature of the surrounding interstellar medium. Neutron star mergers are also predicted to create gravitational waves detectable by LIGO/Virgo. In this project, you will use new data from the Australian Square Kilometre to explore the possibility of large scale surveys for gamma-ray burst afterglows at gigahertz frequencies. You will also use theoretical models to predict the likelihood of detecting afterglows, and help to plan an optimal strategy for conducting unbiased surveys. An interest in developing good computational skills and dealing with large datasets is essential!




Title of Project: Characterising the habitability of exoplanets using radio emission

Supervisor: Dr Christene Lynch

Co-supervisor: A/Prof Tara Murphy


With more than 3300 planets now known outside our Solar System (exoplanets), establishing what criteria define habitability is essential for determining the potential for life on these newly discovered planets. Star-planet magnetic interactions are expected to play an important role in determining habitability. One way to directly measure the magnetic properties of exoplanets is to observe radio emission from the planet. In this project, you will apply existing models of exoplanetary emission to determine which planets are most likely to be detectable at radio frequencies. You will then use data from the Murchison Widefield Array telescope to search for radio emission from all the currently known exoplanets located in Southern Hemisphere. An interest in developing good computational skills and dealing with large datasets is essential!

Title of Project: Exploring the high-frequency radio sky

Supervisor: Prof Elaine Sadler, A/Prof Tara Murphy

Co-supervisor:



Studying the radio sky at high frequencies (20 - 100 GHz) can provide unique physical insights into both nearby and very distant astrophysical objects. The recently-completed Australia Telescope 20GHz (AT20G) survey provided the first large and uniform sample of high-frequency radio sources, and we are offering two projects which use the AT20G data to explore very different aspects of the high-frequency radio sky. One project is a study of compact regions of ionized hydrogen within our own Milky Way galaxy, where radio observations allow us to penetrate the intervening clouds of dust and pinpoint the locations in which unusually massive stars are currently forming. The second project is a study of much more distant galaxies, in which the observed radio emission is powered by the accretion of gas onto a black hole at the galaxy’s centre. The aim here is to measure how the radio emission varies with time, and to find out whether these rare high-frequency radio sources signal the ’switching on’ of a powerful radio galaxy or quasar in the distant universe.




Title of Project: The Bright Radio-Source Population at 150 MHz

Supervisor: Prof Elaine Sadler, A/Prof Tara Murphy

Co-supervisor:



In this project, you will be analysing data from the Murchison Widefield Array (MWA), a powerful new low-frequency radio telescope which has just started operation in a remote region of Western Australia. The MWA has a wide field of view, allowing it to image the whole southern sky at frequencies of 80-230 MHz. In this project, you will investigate some of the brightest low-frequency radio sources revealed by the MWA, using a combination of radio and optical data to identify the dominant physical mechanisms which produce the radio emission. You will be working within a lively and dynamic research group at SIfA, and may also have the opportunity to visit the MWA group in Perth to present and discuss your research results.

Title of Project: Searching for extreme outflows around active supermassive black holes

Supervisor: Dr Elizabeth Mahony

Co-supervisor: Prof Elaine Sadler, Dr James Allison


Active Galactic Nuclei (AGN) are amongst the most luminous and energetic objects in the Universe and are known to play an important role in regulating the growth of galaxies. In some cases, we see outflows of gas being launched at extreme velocities from the central regions close to the supermassive black hole. This project will search for new outflows in young radio galaxies using optical data obtained from the 3.6m NTT telescope in Chile. This can shed light on how galaxies have evolved over the last 6 billion years.

Title of Project: The birth of young radio galaxies

Supervisor: Dr James Allison

Co-supervisor: Prof Elaine Sadler, Dr Elizabeth Mahony


Cold, neutral gas plays a vital role in the formation and evolution of radio galaxies – it is the primary fuel source for both star-formation and accreting super massive black holes. However, it remains difficult to study beyond the local Universe. Using data taken from new radio telescopes, the Australian Square Kilometre Array Pathfinder and the Murchison Widefield Array, this project will search for neutral gas in a sample of distant ‘peaked-spectrum’ radio sources, which are believed to represent the earliest stages in the life of a powerful radio galaxy. This will inform us about the properties of cold gas in these young radio galaxies, and the role it plays in fueling the central supermassive black hole and shaping their subsequent evolution.





Title of Project: Clusters of galaxies: probing their violent history

Supervisor: Prof Dick Hunstead

Co-supervisor:

Email Contact: [email protected] Brief Description of Project or Project Area (5 – 10 lines long):

Clusters of galaxies are the most massive structures in the Universe bound by gravity. They contain hundreds to thousands of galaxies moving at speeds of more than 1000 km/s, stripping gas from member galaxies and heating it by dynamic friction to temperatures >107 K. As well as the hot thermal gas, the intra-cluster medium is a seething cauldron of activity, containing highly relativistic particles and large-scale magnetic fields, which can only be detected at radio frequencies through their non-thermal synchrotron emission. This project will explore the properties of low-redshift clusters selected by their X-ray emission and their detection by the Planck satellite through the Sunyaev-Zeldovich effect. We will use online radio surveys at different frequencies to search for diffuse emission that signifies cluster-cluster collisions, as well as emission from discrete galaxies arising from galaxy-galaxy interactions.

Title of Project: Space-ready micro-spectrographs for Cubesat platforms

Supervisor: Dr Sergio Leon-Saval (Director SAIL labs)

Co-supervisor: Dr Chris Betters


Classical Fourier transform spectrometers (FTS) must translate a mirror while monitoring the interference pattern to make measurements. In this project, we will study and develop a spatial heterodyne spectrometer that replaced the moving mirrors of a Michelson interferometer with reflective diffraction gratings. This should allow a spectrum to be recorded in a fixed format (no moving parts) that will be more suitable for deployments in harsh environments (i.e. CubeSat’s in space). The project will involve both computer aided optical design (using Zemax) and building the optical instrument in the lab. This project is likely to include the development of 3D printed components with the in-house facility. The final aim of the project will be to test the developed spectrograph in space environments (such as high vacuum) with our research collaborators at the Australian National University.




Title of Project: Enabling laser communications in space with multimode photonics



Email Contact: [email protected] Brief Description of Project or Project Area): NASA is developing a trailblazing, long-term technology demonstration of what could become the high-speed internet of the sky. Laser communications, also known as free-space optical communications, encodes data onto a beam of light, which is then transmitted between spacecraft and eventually to Earth terminals. This technology offers data rates that are 10 to 100 times better than current radio-frequency (RF) communications systems. The Laser Communications Relay Demonstration (LCRD) project will help NASA understand the best ways to operate laser communications systems. SAIL labs has recently partnered with NASA Goddard Space Flight Centre to investigate the use of multimode photonics and mode converters known as photonic lanterns coupled to a 1 metre diameter telescope as the earth-based link optical receivers. The aim of the project will be to model, design, fabricate and test a new generation of photonic lanterns multimode to few-mode convertors for this project in direct collaboration with our partners in NASA Goddard Space Flight Centre and NASA Glenn Research Centre.

Title of Project: Measuring the rotation of stellar cores with asteroseismology

Supervisor: Prof Tim Bedding

Co-supervisor: Dr Simon Murphy

Email Contact: [email protected], [email protected] Brief Description of Project or Project Area:

Despite great advances in astrophysics in the past century, open questions in the physics of stellar models remain. One of these questions concerns the rotation of stellar cores, which until recently were impossible to observe. Now, asteroseismology - the study of stellar oscillations - has opened a window to the stellar interior with sensitivity to the interior rotation rates. The results are remarkable. The rotation of red giant stars is two orders of magnitude different from what was expected from theory, and main sequence stars rotate almost rigidly. Only a handful of stars have had their rotation profiles measured, and all of these in the past few years. The breakthroughs have come from ultra-precise data from the Kepler Space Telescope, which monitored the brightnesses of over 150,000 stars simultaneously. Stellar oscillations cause small changes in brightness that can be studied by Fourier transforms of the light curve. This project will examine the rotation profiles of the most promising Kepler targets to uncover the next surprises.





Title of Project: Characterizing Stars observed by the NASA K2 Mission with Skymapper

Supervisor: Dr Simon Murphy

Co-supervisor: Prof Tim Bedding


Following the failure of two reaction wheels on board NASA's planet-hunting Kepler space telescope, the spacecraft was repurposed as the "K2 Mission" to observe different fields along the ecliptic plane. The brand new K2 mission has already collected brightness measurements of over 100,000 stars to detect transiting planets as well as to study rotation and oscillations of stars. However, the characteristics of many of the targets that are observed by K2 are uncertain. The Australian Skymapper telescope has recently released data for a large area in the southern hemisphere, including many fields observed by K2. The project will involve cross-matching the Skymapper catalog with the K2 target list, investigating which Skymapper data products are most sensitive to measure stellar sizes, and improving the characterization of K2 targets (including host stars and their planets).

Title of Project: Are old galaxies thick and young galaxies thin?

Supervisor: Dr Caroline Foster

Co-supervisor: Dr Nicholas Scott


While complex, the process of galaxy formation has led to recognisably distinct types of galaxy structures. These structures can be divided into intrinsically thin, circular disks and thicker, more spherical bulges. However, projection effects and limited sample sizes has prevented reliable measurements of the true 3D or intrinsic shape of galaxies. With the advent of new technologies, we are now able to robustly measure this fundamental property of galaxies. The SAMI team was the first to reliably measure changes in the intrinsic shapes of galaxies with galaxy spin. The SAMI data also strongly suggest that the stellar ages of galaxies and their intrinsic shapes are closely inter-connected. The project will combine the expansive SAMI dataset, spectroscopically determined reliable stellar ages and optimised software to precisely measure the change in the intrinsic shape of galaxies as a function of stellar age. This project offers the possibility to learn and develop programming skills, work with 3D spectroscopy and related methods, participate in the observing on a world-class facility in Australia, as well as a chance to build national and international collaborative links through participation in the SAMI Galaxy Survey.





Title of Project: Liouville's Theorem and single particle motions

Supervisor: Prof Iver Cairns

Co-supervisor:


Electrons moving along magnetic field lines in Earth's magnetosphere are responsible for the aurora and several important radio emissions, including Auroral Kilometric Radiation and planetary continuum radiation. Assuming conservation of energy and magnetic moment characteristic changes in the electron velocity and temperatures are predicted as the magnetic field strength changes. Space observations support these predictions, at least sometimes. Liouville's Theorem appears to contradict these predictions and observations, yet should hold. The project will address these apparent contradictions by explicitly mapping the distribution function and reconsidering the existence or not of electricmfields in the region and the conditions for Liouville's Theorem to hold. The results will be applied to space phenomena at Earth and the outer heliosphere.

Title of Project: Radio emission from upstream of Earth's bow shock


Co-supervisor:


Radio emissions near the electron plasma frequency and its second harmonic are often produced in the foreshock region upstream of Earth's bow shock. The theory involves reflection and acceleration of electrons at the bow shock, generation of Langmuir waves, and production of radio emissions. The project will involve implementing an existing analytic theory numerically, extending it to include a new emission process, and comparing the predictions with satellite observations.

Title of Project: Radio emission from bolides and metal structures entering Earth's atmosphere.


Co-supervisor:


Meteorites and other bolides, as well as spacecraft and human space stations, often enter Earth's ionosphere and atmosphere. Often a shock is expected in front of the object as it enters, with an associated magnetic barrier for a suitably electrically-conducting object. This magnetic barrier can reflect electrons upstream, leading to the growth of plasma waves and radio emission. This project will model the build-up of the magnetic barrier, the electron reflection, and the generation of radio waves, all as functions of properties of the object and local plasma in the ionosphere. The predictions will be compared with certain mysterious radio emissions observed in the last few years and with historical records for re-entering space objects. In a sentence, we will determine whether asteroids, bolides, and re-entering objects like the International Space Station should produce observable radio signals and can explain recently-observed radio emissions.





Title of Project: Murchison Widefield Array observations of type II solar radio bursts


Co-supervisor:


Type II solar radio bursts are each produced in association with a shock wave in front of a coronal mass ejection (CME). The Murchison Widefield Array can in principle produce novel images of the type II radio sources, using analysis codes developed by our group and applied so far only to the source regions of type III bursts. The project will use these codes to image and interpret the source regions of a sample of type II bursts. Phenomena of particular interest include split-band, herringbone, and "multiple lane" fine structures, with topics of special interest including comparisons with CME locations and independent simulations of the type II burst. Comparisons with independent models and simulations will also be performed where possible.

Title of Project: Advanced simulations of type II solar radio bursts


Co-supervisor:

Email Contact: [email protected] Brief Description of Project or Project Area: Type II solar radio bursts are each produced in association with a shock wave in front of a coronal mass ejection (CME). We have developed a novel capability to simulate the properties of specific type II bursts in frequency, time, intensity, and location, as well as the properties of the CME. The project will involve two parts. One is to predict the sensitivity of the radio and CME properties to small changes in the initial direction and speed of a driving CME. The second is to predict the radio and CME properties of a set of type II bursts and to compare these predictions with available MWA and satellite data, both to establish that we can explain multiple type II bursts but also split-band, herringbone, and "multiple lane" fine structures.




Title of Project: The rate of Kepler superflares

Supervisor: Mike Wheatland

Co-supervisor: Don Melrose


Data from NASA's Kepler mission has been used to hunt exo-planets and for asteroseismology, but it also allows identification of stellar flares, which cause transient brightness increases in the light from individual stars (Maehara et al. 2012). These events are the counterparts of solar flares - magnetic explosions in the Sun's atmosphere - but they may be 105 times as energetic. Kepler has shown that stars of all spectral types produce superflares (Balona 2015), and individual stars can be remarkably active, producing dozens of events per day (Hawley et al. 2014). Superflares follow a similar power-law size distribution to solar flares (Shibata et al. 2013), and they are also magnetic in nature. This project will investigate the similarities and differences between the statistics of stellar superflares and solar flares. It will examine the rate at which superflares occur for individual stars, using the waiting-time distribution as a tool for understanding. The results will be related back to the physical mechanisms believed to underlie stellar and solar flares, and new ideas for the flare process being developed by the supervisors. The project has scope for data analysis, theory and modeling. Balona, L. 2015, Monthly Notices of the Royal Astronomical Society 447, 2714 Hawley S. et al. 2014, Astrophysical Journal 797, 121 Maehara H. et al. 2012, Nature 485, 478 Shibata K. et al. 2013, Publications of the Astronomical Society of Japan 65, 49

Title of Project: Electrical current systems and magnetic field topology in the solar corona

Supervisor: Mike Wheatland

Co-supervisor: Don Melrose


Large scale electrical current systems flowing in the ionised solar corona above sunspots provide the energy for solar flares. Because of the high electrical conductivity of the corona, the magnetic field is ``frozen in'' to the plasma and cannot change its connectivity, except during the energy release process (magnetic reconnection) which causes flares. A range of theory has been developed to describe coronal magnetic field connectivity, or field topology. The connectivity of the field is defined by separatrix surfaces between sets of field lines with different connectivity. These surfaces intersect in special lines (separatrices) which begin and end on null points, where the field is zero. In the absence of nulls it is possible to identify "quasi-separatrix layers" (QSLs), defined by large changes in field line connectivity. "Bald patches" are regions where the field is tangent to the photosphere (the solar surface) along a neutral line. The theory describing magnetic topology has largely ignored the role of electric currents. The coronal field is ``force-free'' due to the strong magnetic field and the low plasma density, meaning that currents are everywhere parallel to field lines. However, the currents may vary in magnitude and sign between different field lines. This project will investigate the structure of electrical current systems and their relation to the field topology, using a nonlinear force-free code applied to simple quadrupolar-field boundary conditions. The project will involve a mix of theory, computation, as well as scientific visualisation of three-dimensional vector fields. The numerical work will require use of an existing code, as well as writing new codes to investigate field and current structures.



Research Projects in

Honours Project Offering 2017 v1.1 16

Research Projects in Atomic Molecular and Plasma Physics

Title of Project: Deposition of robust functionalized coatings on pulse-biased substrates

Supervisor: Dr Behnam Akhavan and Prof Marcela Bilek

Co-supervisor:

Email Contact: [email protected] and [email protected]


Plasma polymerization is a versatile surface engineering process capable of depositing ultra-thin functionalized films for a range of applications such as biomaterials for cell attachment and immobilization of enzymes and proteins. In this technology, the desired monomer is initially converted into vapour under a low pressure, and it is subsequently excited into the plasma state using an electric field. The recombination of active species takes place on any surface exposed to the plasma, thus forming a thin layer of

functionalized plasma polymer coating. Production of plasma polymer films that are high in functional group(s) yet stable in body fluids is, however, challenging. This research will be focused on the production of robust functionalized plasma polymer films through judicious choice of plasma deposition parameters. The student will obtain experience in laboratory experiments including both fabrication and characterization of novel engineered surfaces. Credit: Dr Behnam Akhavan

Title of Project: Development of plasma activated coatings on particulate surfaces


Co-supervisor:

Email Contact: [email protected] and [email protected] Brief Description of Project or Project Area:

A plasma activated coating (PAC) is deposited onto substrates via excitation of a precursor gas, e.g. acetylene, in a plasma deposition system consisting of an RF electrode and a pulsed voltage source. PAC facilitates the immobilization of bioactive molecules on the surface owing to highly reactive radicals generated in the coating. While we have successfully fabricated such surfaces onto 2-D substrates, there is great potential to further develop this knowledge for the coating of particulate materials. In comparison with 2-D substrates, plasma polymer-coated 3-D surfaces are of more interest in real-world applications such as protein adsorption/separation and removal of

toxic matter from water. This project will involve designing an agitation system to retrofit an existing plasma deposition system followed by the deposition of plasma activated coatings onto model particulate substrates. The student will obtain experience in laboratory experiments including both fabrication and characterization of novel engineered surfaces.

Credit: Dr Behnam Akhavan







Title of Project: Fabrication of oxidized sulphur-containing films through a plasma-assisted approach


Co-supervisor:

Email Contact: : [email protected] and [email protected] Brief Description of Project or Project Area:

Surfaces containing oxidized sulfur species [−SOx(H)] are of great interest in a number of critical applications including biomaterials, fuel cells, and water purification. SOx(H)-containing surfaces show remarkably high blood compatibility because of their decreased platelet adhesion and anti-inflammatory properties. These surfaces also exhibit enhanced ionic conductivity, which makes them excellent candidates for proton-exchange

membranes. This project will look into the fabrication of such surfaces using a plasma deposition system consisting of an RF electrode and a pulsed voltage source for biasing the substrates. Precursor gas mixtures and deposition parameters will be tuned to achieve desirable sulphur-containing plasma polymer films for the above-mentioned applications. The student will obtain experience in laboratory experiments including fabrication and characterization of novel engineered surfaces. Credit: Dr Behnam Akhavan

Title of Project: Plasma ion implantation treatment of porous polymeric materials

Supervisor: Prof Marcela Bilek

Co-supervisors:, Dr Elena Kosobrodova and Dr Behnam Akhavan

Email Contact: [email protected] and [email protected] Brief Description of Project or Project Area:

Plasma immersion ion implantation (PIII) results in the creation of highly reactive radicals on targeted polymeric materials. These reactive radicals are excellent sites for the immobilization of bioactive molecules. Membranes and porous materials treated via this technique will be of interest for a number of applications including cell culture, tissue engineering and protein adsorption/separation. For such applications, reactive sites should ideally be generated not only onto the surface of a membrane, but also onto the entire internal network of pores. The development of these membranes requires specific reactor designs and geometries that are already available in our laboratories. This project will involve PIII treatment of porous materials under optimized conditions followed by

immobilization/separation of targeted biomolecules. The student will obtain experience in laboratory experiments including fabrication and characterization of novel engineered surfaces. Credit: Dr Behnam Akhavan







Title of Project: Surface enhanced fusion reactions

Supervisor: Joe Khachan

Co-supervisor: Oliver Warschkow


Experiments that produce table-top nuclear fusion, known as inertial electrostatic confinement (IEC), use electric fields to heat and confine ions. The small scale of such a device holds great potential for producing small and portable fusion energy devices – unequalled by any contemporary device. This type of fusion is achieved by focusing ions to a central point using spherical electrostatic grids. In recent experiments, we have found that a substantial part of this fusion occurs at the grid wires and not at the focal point. Further investigations have shown that fusion probability at a metal surface can be enhanced by embedding the hydrogen isotopes in the crystal lattice and relying on the electron density of states around the fusion ion nucleus to shield its Coulomb potential. Any incoming energetic ion approaches the nucleus more closely than an unshielded nucleus. This has the effect of increasing the fusion cross-section (or probability) and therefore can produce higher fusion rates than collisions with the bare nucleus. This is quite a new field of research and the aim is to use computational methods to investigate the enhancement of fusion cross-sections of light hydrogen isotopes embedded in the crystal lattice of various metals. An enhancement in fusion cross-section by three orders of magnitude places this approach in contention as a possible energy producing process. There are experimental results that indicate this is a valid approach. There are also experiments being carried in the School that clearly show the importance of the nature of the metal surface. The tool of this project that you will need to master, with guidance, is known as density functional theory, which is a computational approach to solid state physics. Using density functional theory, you can predict both the binding sites of hydrogen atoms within the crystal lattice, and the electron density that surrounds the atom. This in turn allows you to estimate the Coulomb screening, and thus potentially the fusion cross-section.



Research Projects in Biological, Biomedical and Medical Physics

Title of Project: Bioactive interfaces for cardiovascular implants using plasma discharges


Co-supervisor: Dr Behnam Akhavan and Dr Steven Wise (Heart Research Institute)

Email Contact: [email protected] Brief Description of Project or Project Area: In this project, you will develop and characterise biocompatible plasma activated interfaces for medical implants using state-of-the-art plasma discharge technologies. The work will develop novel High Power Impulse Magnetron Sputtering (HiPIMS) and Plasma Immersion Ion Implantation processes, aiming to synthesise thin films for improving the compatibility of cardiovascular stents. Precursors for the films can be delivered as sputtered vapour or dip-coated natural materials such as Shellac. Electrical and optical diagnostics will be used to explore the most relevant plasma physics during the process. The physical and chemical characteristics of the thin-films will be studied using electron microscopy techniques (TEM, SEM, EDS and EELS), nano-indentation, X-Ray photoelectron spectroscopy (XPS), infrared spectroscopy (FTIR) and ellipsometry. The project is highly interdisciplinary and will involve a continuous collaboration with the Heart Research Institute, where the biocompatibility and mechanical stability of the plasma coated stents will be further studied using in-vitro and in-vivo techniques. You can learn more about our project at the following link: http://www.abc.net.au/catalyst/stories/4145875.htm

Plasma activated coatings on cardiovascular stents made from a range of materials including stainless steel (A and D) and CoCr (B) NiTi (C). All stents were subjected to plastic deformation carried out by crimping and balloon expansion. Scale bars are 100 μm (A), 60 Credit: Miguel Santos and Dr Steven Wise.


http://www.abc.net.au/catalyst/stories/4145875.htm


Title of Project: Plasma pen discharges to activate tissue engineering scaffolds during additive manufacturing


Co-supervisor: Dr Khadijeh Alavi and Prof David McKenzie

Email Contact: [email protected] Brief Description of Project or Project Area: Additive manufacturing (commonly also known as 3D printing) holds great promise in medicine where it can be used to create arbitrarily complex scaffolds for tissue and organ repair/ replacement. The thermoplastic materials optimised for use with these manufacturing processes typically suffer from poor biocompatibility. Our group has developed a number of low-pressure plasma processes that can render such materials not only biocompatible but positively biologically active in that they stimulate and direct desirable cell proliferation. This project aims to develop and characterise localised discharges that can be used to render scaffolds and implantable devices biocompatible during their additive manufacture. The work builds on a prior honours project in which capillary discharges compatible with the additive manufacturing processes were created and their ability to activate polymeric surfaces to enable covalent attachment of biomolecules was demonstrated. In this project, the fundamental physics unpinning the biomolecule immobilisation will be explored. Experiments conducted in controlled atmospheres in which certain atmospheric gas constituents are absent and pretreatment with chemicals that inactivate radicals and other reactive species will be used to eliminate various hypotheses. The physical and chemical characteristics of the plasma-activated scaffolds will be studied using X-Ray photoelectron spectroscopy (XPS) and infrared spectroscopy (FTIR). The project is highly interdisciplinary and will involve a

continuous collaboration with the Charles Perkins Centre, where the biocompatibility of the plasma-modified scaffolds will be studied using in-vitro and in-vivo techniques. Figure: Two plasma pen designs operating in laboratory atmosphere using Argon and Helium respectively as feed gases. Credit: Oliver Charles Lotz and Dr Khadijeh Alavi.



Title of Project: Next generation hybrid materials for biomedical applications


Co-supervisor: Dr Behnam Akhavan and Prof Fariba Dehghani (Faculty of Engineering)

Email Contact: [email protected] Brief Description of Project or Project Area: Hydrogels are cross-linked fibrous materials that incorporate large amounts of water and provide environments for cells that mimic the native aqueous environments of cells in living tissues. Existing technologies allow the creation of a variety of hydrogels that incorporate biological signalling molecules but they lack the structural stability and mechanical strength required for many applications in biomedical implantable devices and sensing. This project will investigate the potential of using plasma surface activation to create hybrid hydrogel materials in which the hydrogel is robustly bonded to a stronger polymeric scaffold. Plasma parameters with a focus on gas flow dynamics and electric field distributions will be tuned to achieve uniform activation of complex scaffold structures. We have already demonstrated that such treatments are possible and that they make the polymer surfaces more hydrophilic and capable of direct covalent binding to hydrogels. The hydrophilic surfaces facilitate easy hydrogel incorporation and the embedded radicals facilitate covalent bonding of the hybrid structures. The physical and chemical characteristics of the plasma-activated scaffolds will be studied using X-Ray photoelectron spectroscopy (XPS) and infrared spectroscopy (FTIR). Together with our colleagues in Engineering, mechanical properties of the hybrid materials will be assessed for suitability for applications in implantable medical devices and microfluidic sensors.

Title of Project: Plasma immersion ion implantation for controlled drug release and biodegradation


Co-supervisor: Dr Behnam Akhavan and Dr Steven Wise (Heart Research Institute)

Email Contact: [email protected] Brief Description of Project or Project Area: Local delivery of drugs and biological from coatings on biomedical implants to prevent infections, mitigate adverse immune responses and facilitate optimal tissue integrations suffers from high initial release rates leading to toxicity and lower than therapeutic release rates thereafter. Biocompatible coatings with tuneable degradation and release rates could solve these problems. Shellac, a fundamentally biocompatible resin secreted by the female lac bug, can be dissolved in ethanol, combined with drugs or biological agents and brushed or dip coated onto arbitrarily complex structures as used in biomedical devices. In this project, we plan to explore the use of ion implantation from a plasma to control the degradation rates of such coatings in aqueous environments and study the effects on drug release rates over time. Ions accelerated by high voltages in a plasma sheath deposit energy tens of nanometers below the coating surface breaking chemical bonds and forming new cross-links in polymeric materials. We have evidence that shows that release of agents loaded into the treated surface layers is inhibited, eliminating the initial toxic burst and that the cross-linking can slow the biodegradation leading to a sustained therapeutic delivery in the long term. An in-depth study of the changes in microstructure, cross-linking and degradation rates is required to allow the production of controlled drug release devices. The physical and chemical characteristics of the ion implanted coatings will be studied using contact angle goniometry, ellipsometry, X-Ray photoelectron spectroscopy (XPS) and infrared spectroscopy (FTIR). Elution assays will be used to




study changes in drug elution rates and biodegradability. Biological testing will be carried out together with colleagues at the Heart Research Institute and colleagues in China.

Title of Project: Multi-functional nanocarriers for targeted therapeutics and imaging (a range of projects available)


Co-supervisor: Dr Steven Wise and Miguel Santos (Heart Research Institute)

Email Contact: [email protected] Brief Description of Project or Project Area: Nanoparticles hold great promise in medicine. In the size range 50-200 nm they can enter cells and deliver cargo including drugs, imaging and targeting agents. An optimum nanocarrier would be able to find a specific target (eg a malignant tumour), deliver a drug and be externally detectable with convenient medical imaging modalities to allow effective monitoring of the treatment. Although there has been a great deal of research on the development of nanoparticles globally, nanoparticles that can be easily functionalised with multiple agents are not available. In recent research, our group has developed and patented a new type of nanoparticle that contains reactive species that enable linking of a wide range of cargo molecules on contact. The attachment of the cargo is achieved through a spontaneous reaction with radicals embedded in the surface of the particle during its synthesis in plasma. We are in discussion with Thermofischer and Merck about the commercial translation of these particles and are conducting a number of engineering, biomedical and basic physics studies to gain a deeper understanding of the mechanisms unpinning their plasma synthesis, behaviour in aqueous solution when mixed with cargo to be attached, mechanisms of reaction, charge-charge interactions that can be used to orient immobilised bioactive molecules and their biological interactions in vitro and in vivo. This work enables many interesting honours projects and can be tailored to student interests.

Nanoparticle production in plasma. Credit Miguel Santos.



Title of Project: Plasma surface engineering of high surface area to volume scaffolds for stem cell expansion and protein/blood purification


Co-supervisor: Dr Elena Kosobrodova, Dr Ali Abbas (Chemical Engineering) and Dr Giselle Yeo and Dr Anna Waterhouse (Charles Perkins Centre)

Email Contact: [email protected] Brief Description of Project or Project Area: Stem cells, found in the bone marrow, are cells that can differentiate into a wide variety of cells and hence they can be used to repair and regenerate tissues all over the body. As such they have great potential in medicine. Despite stunning results that have already been demonstrated in therapies employing stem cells, their introduction in standard treatment modalities is limited by the difficulties and expense arising from the expansion of these cells in vitro (outside the patient). Reactors in which small populations of cells can be used to cost-effectively generate populations 100s of times larger are required. Effective reactors need to have very high surface area to volume ratios as the cells need to adhere to a surface to proliferate and the volume needs to be continuously refilled with costly media, containing nutrients to keep the cells alive. The surfaces need to have physical and chemical properties that facilitate cell adhesion and promote their growth. This project (suitable for more than one student) will develop and employ novel plasma treatments to create optimal cell microenvironments in a variety of inexpensive 3D porous materials and structures including cuttlefish bone and organic polymers. The physical and chemical characteristics of the plasma-activated scaffolds will be studied using X-Ray photoelectron spectroscopy (XPS) and infrared spectroscopy (FTIR) to develop an in depth understanding of how conditions in the plasma regulate the surface properties. In prior work, we have shown that treatments involving energetic ions generate radicals below the surface that can be used to attach biologically active molecules. The radical densities will be quantified using electron spin resonance (ESR) and selected bioactive molecules will be immobilised on the modified surfaces to optimise microenvironments for the growing cells. Incorporation of the structures into bioreactor designs will be done together with Dr Ali Abbas of the School of Chemical and Biomolecular Engineering. Opportunities to utilise the same materials functionalised with antibodies for blood or protein purification devices will be explored together with colleagues at the Charles Perkins Centre.



Title of Project: Microfluidic devices for analysis of blood materials interactions


Co-supervisor: Dr Elena Kosobrodova and Dr Anna Waterhouse (Charles Perkins Centre and Heart Research Institute)

Email Contact: [email protected] Brief Description of Project or Project Area: Blood clots present major and often fatal problems for virtually all implantable blood contacting devices, such as cardiovascular stents, as well as imposing limitations on the processing of blood products from donors. Materials that can make contact with flowing blood without initiating clotting or thrombosis are needed but an understanding of how blood flow in contact with the surfaces of synthetic materials causes clotting or thrombosis is currently lacking. This project aims to create microfluidic devices that can be used to study the clotting behaviour of blood in contact with various materials under a range of flow conditions. Lithographic processing will be used to make microfluidic structures that will be tested with blood in the Charles Perkins Centre together with thrombosis expert, Dr Anna Waterhouse. The surfaces of these devices will be modified using a variety of plasma treatments ranging from low pressure to atmospheric and the effects on thrombosis quantified. The physical and chemical characteristics of the plasma-modified surfaces will be studied using contact angle goniometry, ellipsometry, X-Ray photoelectron spectroscopy (XPS) and infrared spectroscopy (FTIR) to reveal new understanding of the effects of various surface properties on the formation of blood clots.



Title of Project: Bio-functionalization of capsules to maintain insulin secretion, enhance angiogensis and inhibit fibrosis


Co-supervisor: Dr Elena Kosobrodova, Dr Steven Wise (Heart Research Institute) and Prof Peter Thorn (Charles Perkins Centre)

Email Contact: [email protected] Brief Description of Project or Project Area: Diabetes is an increasingly prevalent autoimmune disease that is difficult to manage and predisposes suffers to many life-threatening and debilitating secondary conditions. Since the underlying cause is that the body’s own immune system destroys insulin secreting beta cells, the only cure currently available is to implant beta cells in a capsule that keeps the immune cells out. Such treatments have been successful but they are typically short lived due to difficulties in maintaining effective insulin secreting cell populations within the capsules. In this project, we will explore the use of polymeric hollow fibres of no more than a few hundred nanometres in diameter with pores below 50 nm in size as capsules for beta cells. Plasma treatments recently developed in our group will be used to render both the inner and outer surfaces of the fibres hydrophilic and activated so that functional biological molecules can be covalently tethered. The physical and chemical characteristics of the plasma-activated fibres will be studied using X-Ray photoelectron spectroscopy (XPS) and infrared spectroscopy (FTIR) and correlated to biological outcomes. Biomolecules for functionalising the inner regions of the capsules will be chosen to promote healthy beta cell function whilst those on the outside will be selected to promote angiogenesis (the creation of blood vessels) for effective transfer of insulin into the circulation through the pores in the fibre walls. This project is part of a multidisciplinary research program funded by the US based JDRF. Beta cell studies to evaluate the efficacy of the fibres will be carried out by the team of Professor Peter Thorn in the Charles Perkins Centre and in-vivo assessments of angiogenesis performance will be carried out by the team of Dr Steven Wise at the Heart Research Institute.

Anatomy of a fibre capsule.



Title of Project: Early detection bio-sensors for Alzheimer’s disease


Co-supervisor: Dr Elena Kosobrodova

Email Contact: [email protected] Brief Description of Project or Project Area: As our populations are living longer the incidence of Alzheimer’s disease and other neurodegenerative conditions is increasing. As recent clinical trials failed to show positive effects of promising trial treatments, interest is shifting to early detection combined with measures that can delay the on-set of these conditions. Our research group has teamed up with an Australian spin-off company, AusBiologics Pty Ltd, to develop early detection bio-sensors for neurodegenerative disease. AusDiagnostics has developed proprietary antibodies that interact strongly and specifically with oligomers that appear in a patient’s blood and spinal fluid many decades prior to the on-set of symptoms. The aim of this project is to investigate a number of biosensor concepts that can be employed to detect these oligomers at low concentrations in patient samples. AusBiologics’ antibodies will be immobilised on plasma treated polymer slides and used to capture oligomers from solution. A focus will be on developing protocols using electric fields to maximise the surface density and optimise the orientation of the immobilised antibodies to provide the lowest possible detection limit. Orientation will be studied using time-of-flight secondary ion mass spectroscopy (tof-SIMS). Detection based on optical and infra-red sensing will be explored in parallel using spectroscopic ellipsometry and Fourier transform infra-red microscopy respectively.

Sensor in the form of an antibody microarray Credit: Dr Elena Kosobrodova



Title of Project: Emergent brain-like behaviour from atomic switch networks: Towards Neuromorphic AI

Supervisor: Prof Zdenka Kuncic

Co-supervisor: Dr Paula Sanz-Leon


Brief Description of Project or Project Area: Atomic switch networks (ASNs) are a post-CMOS technology developed for computer electronics. Currently, interest is growing in their potential as associative memory and learning devices for neuromorphic artificial intelligence (AI) applications. This project involves complex systems modelling of emergent brain-like behaviour, such as memory and learning, from neuromorphic atomic switch networks. This project will combine mathematical and computational modelling based on an experimental prototype and an in-house developed toolbox to simulate ASNs. The main goals of this project are (1) to develop a more detailed single switch model; (2) to characterize of the collective spatial-temporal nonlinear dynamics of the system that regulate memory, learning and other AI features; and, (3) to make a quantitative comparison of network dynamics between simulated and experimental data.

Title of Project: Modeling of sodium channels

Supervisor: A/Prof Serdar Kuyucak

Co-supervisor:


Sodium channels play important roles in many aspects of cellular function such as propagating the action potential in nerves. However, due to lack of molecular structures for mammalians, progress in the field of sodium channels has been very slow. After decades of trials, the first high-resolution structure of a sodium channel from insects has finally been determined (Science, 355:924 (2017)). The aim of this project is to construct the mammalian homologue from this structure, and perform molecular dynamics simulations to investigate the ion permeation and selectivity mechanisms in sodium channels. This will lay the foundations for future work on medical aspects of sodium channels (e.g., how neurological diseases are caused by dysfunctional channels), and pharmacology (e.g., targeting dysfunctional sodium channels with drugs to modulate their behaviour).

mailto:[email protected]?subject=Honours%20project



Title of Project: Developing drugs using toxin peptides from plants

Supervisor: A/Prof Serdar Kuyucak

Co-supervisor:


Many toxins bind to ion channels affecting their normal operation. Because of their high affinity and specificity, toxins provide ideal leads for developing drugs that target diseases caused by dysfunctional ion channels. At present this search is mostly carried out on a trial and error basis, which is not very efficient. A better understanding of the toxin-channel interactions would lead to a more rational design of drugs from toxins. In this project you will study the binding of selected novel toxin peptides from plants to Kv1 voltage-gated potassium channels using simulation methods such as molecular dynamics and docking. The aim of the project is to find the key residues involved in the binding and study their mutations to see if a mutant version can be developed which has a higher affinity for the Kv1.3 channel (target for autoimmune diseases) but not for other Kv1 channels.



Research Projects in Complex Systems

Title of Project: When does opinion polarisation occur?

Supervisor: Dr Tristram Alexander

Co-supervisor:

Email Contact: [email protected] Brief Description of Project or Project Area: Social scientists have identified numerous ways people react when confronted with opinions which differ from their own. The outstanding challenge is to translate these observations at the small scale to a description of the dynamics of an interacting population. Physicists have made early attempts at doing this, studying the implications of simple rules on the emergent properties of a large population. However, there is one emergent behaviour which is still not understood, the formation of polarised camps of opinion which ignore or are antagonistic to each other. This is despite the prevalence of such behaviour in everyday life, with examples in politics, attitudes to climate change, and even concerning whether children should be vaccinated or not. In this project, a model of opinion dynamics will be introduced, based on rules of interaction identified in small scale experiments. By scaling up to many interacting individuals this project will seek to identify the necessary and sufficient conditions for polarised camps to form. The project will then examine the implications of these polarisation dynamics, identifying for instance when “echo chambers” form, and whether these lead to an increase in extremism. The predictions will be validated by considering readily available social media data.

Title of Project: Social contagion in the presence of cost


Co-supervisor:


It has been widely observed that particular behaviours may spread through a population much like a disease, but seemingly passed on through observation and imitation. While social scientists are divided over what exactly defines such behaviour as “social contagion”, physicists have leapt at the opportunity to study this phenomenon, typically focusing on the mechanisms of spread and the role of network connectivity. However, while there has been widespread interest in the physics community in examples such as rumour spreading, the spread of innovation, and even consumer spending, there has as yet been no consideration of the possibility of social contagion when in the presence of a cost to the spreader. This is particularly relevant to any opinion expression when speaking out has negative consequences, such as protest when under threat of repression or whistleblowing. In this project, new models of social contagion incorporating cost will be introduced. Both probabilistic models and “integrate-and-fire” type models will be considered, and the signatures of contagion will be identified. This will be compared to typical progressions of social contagion in the presence of cost observed in social media movements.




Title of Project: Data Analysis and Modelling of Visual Thalamus in the Brain, using an Engineering Control Approach

Supervisor: Dr Tara Babaie

Co-supervisor: Prof Peter Robinson


Brief Description of Project or Project Area: The brain is the most complex live object in the known universe. The ultimate brain function is being under rigorous research for decades. Great advances in neuroscience over the past two decades, aided by technological innovations in several modalities of brain data collecting, as well as increased sophistication in computational theory, have inspired many theories to explain the brain’s functionality. In this project, we explore a dynamical system approach inspired by control engineering and big data science to address the fundamental problem in the brain research: how our brains make sense of the world? Focusing on visual modality in the brain, we study a corticothalamic model raised from mammalian brain's anatomy and collecting a massive experimental data set regarding brain's response to a particular signal from retina, we would propose a dynamical model to explain the visual function in the thalamus and just before the signal arrives in the cortex. The applicant for this project will require computational skills in linear algebra and statistics as well as Matlab programming. The student will be carrying out data analysis tasks along with mathematical/statistical modelling. Accomplishing this project, the student is expected to learn how to perform in a research environment and acquire basic skills to follow a higher education program in computational science.

Title of Project: The Role of Attention in Dynamics of Large-Scale Brain Activity

Supervisor: Dr Tara Babaie


Email Contact: [email protected] Brief Description of Project or Project Area: Until recently, visual attention and awareness in primates were thought of as purely cortical phenomena. Recent thought-provoking data, however, confirm some previous neuroimaging demonstrations of attentional modulation in the primate thalamus, namely lateral geniculate nucleus (LGN) and thalamic reticular nucleus (TRN). The vast majority of visual information from the retina passes through thalamic relay cells in the LGN of the thalamus then passing through the TRN before reaching visual cortex. Both thalamocortical and corticothalamic neurons emit excitatory collaterals within the TRN which suggests a possible modulatory role for the TRN in controlling thalamic activity. The aim of this project is to improve theoretical models of thalamic sensory processing for which we need to investigate the role of attention in terms of parameters and or structure within the physiological representation of visual attention in whole model of brain. This project at the core is involved with the identification of a theoretical model for attention, including the associated neural parameters.




Title of Project: Eigenmodes of resting state brain connectivity vs. resting state network: a test case study

Supervisor: Dr Demi Gao




The normal brain is always active and processing incoming signals, even if not consciously. The “resting state” interactions that occur when a subject is not performing an explicit task are often evaluated using low-frequency functional magnetic resonance imaging (fMRI). It has been widely observed that “resting state” brain activity has distinct robust patterns, which are often called “resting state networks” (RSNs). Common methods used to define RSNs, e.g., Principal Component Analysis (PCA), extract orthogonal components of the signal. However, these methods are based in statistics not brain physiology. Using neural field theory (NFT) developed in our group, our recent studies decomposed the brain activity into eigenmodes, which provides a physics based perspective on brain connectivity. Most recently, our preliminary results showed some similarity between eigenmodes and RSNs. However, exact comparison is required and it remains to be seen whether eigenmode dynamics and structure can explain the properties of RSNs. To address these questions, we will start from a test case. First we use neural field model to generate simulated NF activity in a one-dimensional space; then we calculate RSNs using PCA based on the simulated NF activity, we will also decompose the activity into eigenmodes; finally, we will conduct a thorough comparison between the RSNs and eigenmodes in our test case. If time allows, we verify our results using experimental fMRI data (available from ARC Center of Excellence for Integrative Brain Function, in which Prof. Robinson is a Chief Investigator).

http://www.arc.gov.au/arc-centre-excellence-integrative-brain-function


Title of Project: Statistical properties of structural and functional brain connectivity




To better understand how brain processes inputs and performs tasks rapidly, how it maintains stability while preventing the spread of undesirable activity such as seizures, how it develops, and how it responds to damage have provided much of the motivation for the current brain research, e.g., the Human Connectome Project. The brain connectivity is often quantified via connectivity matrices (CMs). In particular, anatomical CMs (aCMs) summarize the known anatomical connectivity between brain regions, functional CMs (fCMs) are determined from the correlation of activity in brain regions using low-frequency functional magnetic resonance imaging (fMRI), and effective CMs (eCMs) quantify the neural effect of one region to another. Our previous studies have used neural field theory (NFT) to relate the eCMs to bare and dressed field propagators, and have interrelated CMs using eigenfunction analysis. However, we do not yet fully understand the statistical properties of connectivity, for example, some of the effective and functional connectivities are negative even when anatomical connectivities are all positive. To address these questions, we first interrelate CMs using NFT and eigenfunction analysis; then we predict and explain the distribution of effective and functional connectivity using theoretical analysis; finally, we verify our result using experimental connectivity data (available from ARC Center of Excellence for Integrative Brain Function, in which Prof. Robinson is a Chief Investigator).




Title of Project: Brain mechanisms of memory consolidation during sleep

Supervisor: Dr Dongping Yang



In many computational studies, cortical dynamics are operated in a linearly stable domain, but the studies of human EEG show significant autocorrelation, which requires non-linearity. The bifurcation in nonlinear dynamical systems can be indicated by statistical properties such as increased autocorrelation length, increased variance, power law scaling, and critical slowing down. However the reliability of these generic indicators depends on the alignment in phase space between the input noise vector and center eigenspace at the critical point. Therefore, it is important to understand the low-dimensional dynamics of cortical models near instability, and the sensitivities of each part of the system.

Title of Project: Numerical solutions for determining brain network connectivity from activity correlations



Email Contact: [email protected] Brief Description of Project or Project Area: The brain connectivity is often quantified via connectivity matrices (CMs). Previously, we showed how to relate neural field theory (NFT) propagators to effective connection matrices (eCMs) (the connectivity strength between brain regions via direct and indirect paths), and how to interrelate eCMs to functional connectivity matrices (fCMs, determined from the correlation of activity in brain regions using low-frequency functional magnetic resonance imaging (fMRI)). Most recently, we inferred eCMs from fCMs including time delays and frequency dependency, which are crucial for understanding many brain phenomena. This method is based on a causal spectral factorization method, and has been verified against analytic solutions and case studies. However, an effective numerical solution of this method is lacking at this moment, e.g., i) what is the most efficient numerical solution method for spectral factorization, and ii) how can one effectively calculate eCMs from fCMs for complex connectivity (e.g., large matrix size). To develop an effective numerical solution, we start from study of NFT and its theoretical method for inferring eCMs; then we develop numerical implementations of our algorithm using Matlab and/or C++; finally, we test our algorithm in more complex experimental connectivity data (available from ARC Center of Excellence for Integrative Brain Function, in which Prof. Robinson is a Chief Investigator).





Title of Project: Wake-sleep transition: probing early warning signals

Supervisor: Dr Dongping Yang



It is of great importance to have warning of imminent wake-sleep transition, because of its critical safety implication for workers in the transport industry, air traffic control, and other safety-sensitive occupations. Phenomena of a sudden transition from one state to another occur in a wide range of complex systems, including earthquakes, climate tipping and ecological stability. For a simplified scenario, a recent physiologically-based model of the ascending arousal system will be used to analyse the dynamics near the transition, and then multiple time-scale analysis will be employed to understand such pre-transition phenomena and to estimate the timing before this critical transition.

Title of Project: How does the brain compute? Distributed dynamical computation in neural circuits

Supervisor: Dr Pulin Gong

Co-supervisor:

Email Contact: [email protected] Brief Description of Project or Project Area: One of the most fundamental problems about the brain is how it computes. To answer this question, recently we have presented a concept of distributed dynamical computation (DDC), in which computation or information processing is carried out by interacting, propagating neural waves. The concept can merge dynamics and computation aspects of the brain, which used to have great gaps between each other. The project will involve making further links between dynamics and computation, including studying our current models of spiking neural networks with synaptic dynamics to present novel solutions to associative memory and visual feature binding in pattern recognition, and comparing the distributed parallel computation capacities of DDC with those of conventional distributed computation paradigms.

Title of Project: The physics of working memory in the brain


Co-supervisor:


Working memory, a core cognitive function, is responsible for the transient holding, processing, and manipulation of information. Its neural correlate (persistent firing activity of neurons), as shown in latest experimental studies, has great variability and is topographically organized in the form of spatial gradients. These properties along with the power-law forgetting behaviour of working memory can’t be explained by conventional models with homogenous stable states. In this project, a new physical mechanism of working memory, which is based on interacting, localized Turing-like patterns, will be studied. Particularly, the collective subdiffusive dynamics emerging out from these patterns will be used to account for the key dynamical properties and coding accuracy of working memory.





Title of Project: Turbulence in the brain: Detection of dynamic coherent structures in collective neuronal activity


Co-supervisor:


Cortical neural circuits are complex, non-equilibrium systems whose collective dynamics cannot be described solely in terms of oscillations or even low-dimensional aperiodic (chaotic) dynamics. Very recently, we have developed a method that enables us to make new discoveries regarding the collective dynamics of neural circuits; for instance, we have found dynamic coherent structures such as vortices in the population activity of neurons. This new finding therefore makes cortical spatiotemporal dynamics analogous to that in turbulence fluids, in which a hierarchy of coherent structures are similarly embedded in stochastic spatiotemporal processes. This project will involve further developing this new method, analysing neural data collected by our collaborators at Imperial College London, and modelling the dynamic coherent structures by extending the models developed by our group. The results of this project would significantly advance our understanding of complex brain dynamics underlying flexible cognitive function. For this project, students will have the opportunity to learn essential skills for big data analysis and modeling.

Title of Project: Googling the brain: Search of associative memory


Co-supervisor:


Human memory has a vast capacity, storing all the knowledge, facts and experiences that people accrue over a life time. Given this huge repository of data, retrieving any one piece of information from memory is a challenging computational task. In fact, it is the same problem faced internet search engines that need to efficiently organize information to facilitate retrieval of those items relevant to a query. It is therefore of fundamental and practical importance to understand what kind of dynamics and algorithms are used for searching memory in the brain. Very recently, we have developed a biologically plausible neural circuit model, which can quantitatively reproduce salient features of memory retrieval. This project will involve further developing the model based on latest experimental results to unravel principled dynamics of memory search. These principled dynamics will then be used to develop a novel searching algorithm applicable to the huge repository of data as used by the Google search engine.




Title of Project: Chronophysics of glucose metabolism

Supervisor: Dr Svetlana Postnova

Co-supervisor: Prof Zdenka Kuncic


Internal circadian (~24 h) clocks drive every system in the human body: from circulation and cognition to metabolism, and mood. Disturbances of circadian rhythms are linked to multiple diseases that could potentially be treated and/or prevented by application of circadian principles to design interventions. In particular, disturbances of circadian rhythms in glucose metabolism are associated with higher risk of obesity, diabetes and cardiovascular disease. In this project, we aim to build up on existing models developed at the Complex Systems and Biophysics groups at the School to develop a physiologically based model to account for the effects of the circadian clocks on glucose metabolism. This will allow us to better understand the mechanisms of glucose regulation and lay the groundwork for real-world applications and interventions. This project involves collaboration with the Charles Perkins Centre (CPC) and would suit a student who is interested in computational/theoretical biology.

Title of Project: Occupational applications of alertness models


Co-supervisor:


Disturbances in alertness due to poor sleep and/or irregular work hours, such as in shiftwork, are a significant hazard leading to high risk of accidents at workplace and on the roads. Bio-mathematical models of alertness have been developed to understand the mechanisms of alertness dynamics and predict alertness in occupational settings. At the Complex Systems group we have developed a physiologically based model that accounts for various factors affecting alertness and sleep; e.g., light, sleep inertia, and substances (e.g. caffeine). However, it is unclear which model is best for use in real-world as they have not been directly compared. In this project, we will test a set of to (i) explore their agreement with experimental data, (ii) understand their strengths and limitations, and (iii) underpin the key areas for further research. The project involves collaboration with the CRC for Alertness, Safety and Productivity, and suits a student who is interested in coding and computational/theoretical biology.




Title of Project: Stretched exponents in a sleep brain


Co-supervisor: Dr Paula Sanz Leon, Prof Peter Robinson


Chronic sleep restriction is inherent to the modern society, especially for those working shifts or sleeping less on workdays compared to weekends. It results in significantly elevated levels of sleepiness and longer reaction time which are underestimated by subjective assessment. New biological mechanisms have been recently discovered describing the accumulation and clean-up of toxic metabolites in the brain during wakefulness and sleep that suggest a novel approach for modelling the accumulation of sleep debt. In this project, we will build up on the physiologically based model of sleep and alertness developed in the group to develop a prototype model based on these new mechanisms. This project will thus test the biological hypothesis and lay the groundwork for an improved model of sleep and alertness. The project involves collaboration with the CRC for Alertness, Safety and Productivity, CoE for Integrative Brain Function. It suits a student who is interested in computational biology and has strong maths skills.

Title of Project: Dynamic and spectral features of distributed time-delays in the brain

Supervisor: Dr Paula Sanz-Leon

Co-supervisor: Prof. Peter Robinson



Transmission delays are inherent in physical systems. Neural waveforms and information propagation strongly depend on the type and distribution of time delays. In the brain, axonal transmission delays can be grouped into two categories: (i) delays within a given structure s͑uch as within the cortex͒; and, (ii) delays between distinct structures s͑uch as between cortex and thalamus͒, on which our group has done analytic predictions using Neural Field Theory (NFT). The first part of this project will combine our group’s theoretical expertise (NFT) and in-house developed software (Neurofield) to study spatial wave interactions and how the neural waveforms change under distributed delays, including the effects of spatial propagation along the cortex. The second part of the project consists of (1) spectral analysis of simulated data; and, (2) quantitative comparison between simulated and real electroencephalographic (EEG) power spectra. The outcomes of this project will provide a quantitative model to explain the spatial distribution of spectral peaks across the cortex as observed in experiments. The project involves collaboration with the ARC Centre of Excellence for Integrative Brain Function on which Prof. Robinson is a Chief Investigator.




Title of Project: Dynamics of insomnia and sleep disorders

Supervisor: Dr Paula Sanz-Leon

Co-supervisor: Dr Svetlana Postnova, Prof. Peter Robinson



Sleep is vital for healthy brain function. Insomnia and sleep apnoea are two major sleep disorders characterised by poor sleep quality, which impairs performance among many other negative effects on health. We will combine our group’s expertise in neural field modelling, arousal-state modelling and an in-house developed software (BrainTrak) to achieve the three main goals of the project: 1) derivation of underlying physiological parameters in adults with insomnia and sleep apnoea; 2) quantitative comparison of electroencephalography (EEG) recordings between poor and healthy sleepers via spectral analysis; and, 3) characterisation of the temporal dynamics during sleep onset in poor sleepers. The outcomes of this project will provide a quantitative classification of sleep disorders to assist with their diagnosis and treatment. The project involves collaboration with the Woolcock Institute of Medical Research, the Charles Perkins Centre and the NHRMC-NeuroSleep Centre of Research Excellence on which Prof. Robinson is Chief Investigator.

Title of Project: Dynamics of optogenetic stimulation in monkey cortex

Supervisor: Dr. Cliff Kerr

Co-supervisor: Dr. David Kedziora


Optogenetics is a powerful procedure for performing precise perturbations to continuing cortical dynamics in awake animals. However, current methods allow for only small numbers of neurons to be recorded simultaneously. Using data from one of the world’s leading primate optogenetics labs (via an international collaboration with Stanford University), this project will explore how spiking neuronal network models can be used to leverage these data into a more detailed understanding of the effects of optogenetic stimulation. Specifically, this project will explore the limits of how neuronal dynamics can be shaped via optogenetic stimulation, as well as the impact of this stimulation on information flow and computation in the brain.





Title of Project: Modeling of nonuniform brain waves using WKB methods and Neural Field Theory

Supervisor: Dr James MacLaurin


Email Contact: [email protected] [email protected] Brief Description of Project or Project Area:

Many types of brain waves are found to be highly nonuniform and to have preferred directions of propagation. These include 10 Hz alpha waves, which dominate during relaxed waking states, particularly toward the back of the brain; 40 Hz gamma waves, which are found to correlate with perception and to precede certain seizures that break out from foci; 4 Hz theta waves, which are propagate through the hippocampus and are linked with spatial navigation; and 1 Hz PGO waves that propagate from front to back of the brain during deep sleep. However, there is as yet no clear set of theoretical predictions or explanations of why this broad range of waves all exhibit similar non-uniform structure and preferential propagation characteristics. Macroscopic brain activity can be predicted Neural Field Theory, which yields a set of coupled partial differential equations for resulting brain waves. This project involves the analysis of wave modes by approximating the neural field equations using WKB expansion methods from quantum physics. This will enable prediction and interpretation of mode structure and propagation characteristics, in the various situations mentioned, which have wide application to brain phenomena and disorders. The results will be tested against real brain data.



Nanoscience


Research Projects in Nanoscience

Title of Project: Evaluating a magneto-radio-sensitive nano-probe for the Australian MRI-Linac

Supervisor: Hilary Byrne

Co-supervisor: Prof Zdenka Kuncic


This project investigates the capability of Gadolinium (Gd)-based nanoparticles to enhance radiotherapy while simultaneously providing contrast for Magnetic Resonance Imaging (MRI). Gd has a high cross-section for radiation interactions compared to biological tissue. It is also paramagnetic and thus an excellent MRI contrast agent. This project will develop protocols for measuring the radiation dose enhancement from Gd nanoparticles, backed up with Monte Carlo particle simulations. The final application is evaluating the dose enhancement on the Australian MRI-Linac at the Ingham Institute in Liverpool. This research facility combines an MRI scanner with a linear accelerator allowing real-time imaging during radiation treatment, and is unique in Australia.

Title of Project: Hierarchical assembly of DNA nanostructures

Supervisor: Dr Shelley Wickham http://sydney.edu.au/science/people/shelley.wickham.php

Co-supervisor:


To physical and chemical scientists, DNA has huge potential as a programmable building material for biocompatible nanostructures. To us, short DNA strands are like smart molecular lego pieces, which can assemble themselves into the shapes we design. My group takes an interdisciplinary approach, combining physics, chemistry and biology, to develop DNA nanostructures as tools for biophysics, platforms for diagnostics and therapeutics, and templates for nanofabrication. Projects are welcome in these application areas, and many other related fields. This project aims to take inspiration from biological systems and use hierarchical assembly to combine many DNA nanostructure building blocks into a larger assembly, in which the cooperative interaction of many simple elements leads to a complex system exhibiting emergent behaviours. This project involves a large amount of creativity, and will involve: computer aided design and modelling of DNA nanostructures, assembly and analysis with transmission electron microscopy (TEM), atomic force microscopy (AFM), and fluorescence imaging.




Title of Project: Project 2: Top down meets bottom up nanotechnology

Supervisor: Dr Shelley Wickham http://sydney.edu.au/science/people/shelley.wickham.php

Co-supervisor:


In traditional top-down nanofabrication (e-beam, photolithography), large and expensive systems are used to pattern a semiconductor substrate in serial steps to build up sophisticated devices, such as the integrated circuits used in virtually all modern electronic equipment. In contrast, in the emerging field of bottom-up nanotechnology, clever design of molecular interactions leads to the self-assembly of smaller building blocks into larger and more complex structures, in a parallel process, with much smaller features. We aim to combine the strengths of both these techniques, by building hybrid structures in which an array of DNA nanostructures is precisely arranged on a photolithography patterned surface. This array can then act as a nano-breadboard, for example to arrange other nanoparticles and proteins for high throughput imaging analysis.



Research Projects in Condensed Matter Physics Title of Project: Investigating spin-dependent conductance in transition-metal porphyrin-graphene nanohybrids

Supervisor: Prof. C. Stampfl

Co-supervisor: Dr. C. Cui, S.A. Tawfik


Brief Description of Project or Project Area Metal porphyrins constitute a class of versatile molecules that play an important role in diverse branches of science, such as biochemistry and materials science. For example, metal porphyrins, metal phthalocyanines and related organic metal complexes have been considered as light absorbers in solar cells, and porphyrin molecules perched between electrodes made of metal clusters or graphene have been suggested in the context of molecular electronics. In the present project, the adsorption of transition metal porphyrins on defected graphene and its consequences for electronic transport in these nanohybrids will be investigated by means of density functional theory and quantum transport calculations. Properties of interest are the stability, magnetic properties, spin dependence of conduction, and whether the latter is (metal) element-specific. The output of this project is expected to lead to a journal publication. (Involves collaboration with Germany)


Title of Project: Innovative multiferroic material design from first-principles theory calculation


Co-supervisor: Dr. Jianli Wang


Brief Description of Project This project will investigate puzzling complex phenomena in multiferroics with the aim of designing new materials for the possibility of using multiferroics in novel electronic device applications. Selected compounds will be studied using first-principles quantum mechanical calculations (carried out on high performance computing facilities) which will reveal the atomistic interactions that are responsible for the electrical polarization of rare-earth orthoferrites and orthochromites, as well as novel multiferroics via defect-engineering and heterostructure formaton. A deep knowledge of complex electronic/magnetic phenomena in bulk and nanomaterials will be gained, which is essential for the understanding and design of devices with enhanced and/or new functionalities.

(Example of the structure of a multiferroic heterostructure)


Title of Project: Functionalisation of silica-alumina-based nano-catalysts for production of biofuels and chemicals


Co-supervisor: Dr. C. Cui, A/Prof. J. Huang


Brief Description of Project or Project Area

Improvement in the sustainability and productivity of the chemical industry is urgently required to meet the increasing demand for fuels and chemicals and the impending depletion of fossil-based resources. Presently, solid acid catalysts play and increasingly important role not only in production of transportation fuels and petrochemicals, but also in generating renewable fuels and chemicals from biomass. Silica-alumina-based catalysts are most commonly used, whereby varying the Si/Al ratio in zeolite synthesis, the acidity can be tuned. At present however, a detailed understanding of the atomic scale mechanisms responsible for this is lacking. This project will address key questions regarding the fundamental physics and chemistry of these novel solid acid nano-catalysts with the overall goal of understanding and predicting their structure and reactivity. The studies will be carried out using first-principles quantum mechanical density-functional theory calculations on supercomputer facilities. The output of this project is expected to lead to a journal publication. (Involves collaboration with School of Chemical Engineering)

Title of Project: Atomic-scale Characterisation of Semiconductor Nanowires

Supervisor: A/Prof Rongkun Zheng

Co-supervisor: Simon Ringer


Semiconductor nanowire heterostructures are promising for nanoelectronic, nanophotonic and nanooptoelectronic devices due to their superior electrical and optical properties compared with other materials. Precise control over the composition and perfection of interfaces is required for the successful fabrication of high-performance devices. This project aims to understand the origin and nature of variations in composition and interfaces and to thereby improve the quality of nanowire heterostructures. By developing growth-structure-property relationships, we will be positioned to grow high-quality nanowire heterostructures suitable for various devices.



Title of Project: Graphene: a journey of appreciation and exploration via computational simulations


Co-supervisor: Dr Carl Cui


Graphene, single atomic layer of graphite, exhibits truly spectacular structural, mechanical, electronic, thermal and possibly magnetic properties. Graphene and its derivatives hold promise for a vast range of nanotechnologies, particularly in the emerging field of graphene-based nanoelectronics and nanospintronics. This project aims to study several key graphene-based nanostructures including nanoribbon, nanodots and nanoantidots. Their optical, electrical and magnetic properties will be investigated by the state-of-the-art first principles (no experimental parameters) simulations. The output of this Honour project is expected to result in 2 international journal publications.

Title of Project: Development of high performance NdFeB permanent magnets


Co-supervisor: Martin Xu


NdFeB-based permanent magnets have been widely used in many industries such as communication, electronics, information and transportation. Comprehensive investigations are needed on their processing conditions, microstructure as well as magnetic properties. This project, in collaboration with industry partners, will clarify processing-structure-property relationships in NdFeB permanent magnets and optimise the microstructure control for better performance.




Title of Project: Removing a major driver of Climate Change

Supervisor: Dr Cenk Kocer

Co-supervisor:


The Intergovernmental Panel for Climate Change has clearly shown that the short and long term pathway to significantly alter the growing issues of climate change is to reduce energy waste in our residential and commercial buildings. In all developed countries there is as much as 40% uncontrolled energy loss in buildings: through the windows. At the University of Sydney, we were the first to invent, and commercialize in 1998, a highly thermally insulating window that outperforms all existing technologies in the field; the Vacuum Insulated Energy-Efficient Window. VieW is a unique low weight, low profile, highly thermally insulating technology that is constructed from two flat sheets of glass, separated by an array of high strength spacers, with the gap between the glass evacuated to a low pressure. The glass panes are hermetically sealed at their edges to maintain the vacuum of the unit indefinitely. Since the gap between the glass panes is evacuated, atmospheric pressure acts on the surfaces of the glass panes at about 10,000 Kg m-2. The VieW project group is highly industry orientated with multiple partners from the glass and manufacturing industries. The group is offering projects that would be looking at the thermal, mechanical and vacuum stability, performance metrics of the VieW system. Students would be using a range of experimental techniques from plasma, laser and residual gas analysis methods, to explore the VieW parameters of interest. In parallel there are high performance computing resources available to perform various numerical simulations to characterize the glazing performance further. Students are encouraged to engage and discuss possible projects, come to see the current lab work, and during their project interact with industry partners to solve the real-world problems to bring the next generation VieW technology to market.



Research Projects in Particle Physics

Experimental Physics

Title of Project: Simultaneous measurements of Standard Model cross-sections at the Large Hadron Collider

Supervisor: Prof. Kevin Varvell Co-supervisors: Email Contact: [email protected], Brief Description of Project or Project Area:

The Large Hadron Collider is designed to produce exotic particles such as the Higgs boson, top quark, and W and Z bosons by colliding protons together and using gigantic detectors like ATLAS to examine the debris. By fitting data collected by ATLAS to predictions made by the Standard Model, the model which describes all fundamental interactions of elementary particles, we can simultaneously study the production mechanisms of several rare processes. This simultaneous measurement allows us to perform a global test of the Standard Model which has the potential to reveal new physical processes beyond the Standard Model. This work would be suitable both for standalone honours projects and for projects leading into subsequent PhD research.

Title of Project: Data acquisition for an upgraded ATLAS detector at a High Luminosity Large Hadron Collider

Supervisor: Prof. Kevin Varvell

Co-supervisor:


In the future, the Large Hadron Collider at CERN will be upgraded to high luminosity running (the so-called HL-LHC) and this will require the giant detectors such as ATLAS to undergo their own upgrades in order to be able to collect data at significantly higher rates. Planning for this is already underway, and in this project a local test-stand for studying fast read-out possibilities for the new ATLAS inner tracker (ITK) will be developed. A student doing this project might expect to learn about how particle physics detectors collect their data and gain some experience of programming FPGAs (Field-Programmable Gate Arrays).



Title of Project: A first look at semileptonic decays in the Belle II experiment

Supervisor: Prof. Kevin Varvell

Co-supervisor:


Brief Description of Project or Project Area: The Belle II experiment at the SuperKEKB electron-positron collider in Japan, which is currently being commissioned, will primarily aim to study rare decays of B mesons. Initial data is expected early in 2018, and in this project that data will be examined to make an initial seacrch for “semileptonic” decays of B mesons, where the products of the decay are a lighter meson than the B, a charged lepton such as an electron, muon or tau, and a corresponding neutrino. Decays of this type enable us to probe fundamental parameters of the Standard Model of particle physics (SM), and to search for possible evidence for the SM breaking down.

Title of Project: Searching for exotic mesons at ATLAS in final states including neutral particles

Supervisor: A/Prof Bruce Yabsley

Co-supervisor:


Many exotic mesons — particles that do not have the quark-antiquark structure of the established mesons — have been seen since 2003. The best-known of these states is the X(3872). One model of its structure is that it is _two_ mesons, a D0 and a D*0bar, weakly bound by pion exchange (like a proton and a neutron forming a deuteron). Many have speculated that there should be a related state, an "Xb", made of B0 and B*0bar mesons. The search for an Xb in LHC Run 1 data, at the ATLAS experiment, was performed here in Sydney using a four-charged-particle final state. To fully exploit the large Run 2 dataset, the analysis method needs to be changed, to also include a gamma ray in the final state. This change introduces challenges in the reconstruction, but also provides a rich set of observables that can be used to suppress background processes. In this project, you will help to study and design such a search. There is potential for this work to lead to a future postgraduate project.




Title of Project: Proton-antiproton decays of standard and exotic mesons at Belle II

Supervisor: A./Prof. Bruce Yabsley

Co-supervisor: Dr Frank Meier



All of the standard charmonium states, such as the famous J/ meson discovered in 1974, have a proton—antiproton decay mode. Since 2003, a number of exotic mesons — resembling charmonium, but lacking its quark-antiquark structure — have been seen. It is not known whether these exotic states also decay to a proton and an antiproton. It is very important to determine whether this decay occurs, and if so, at what rate: future experimental facilities depend on this information. Searches for this decay at Belle II, due to start taking data in 2018, should be competitive. Previous searches at Belle have included tracking information for the proton and antiproton, but have ignored the response of the electromagnetic calorimeter to these particles. We are currently calibrating the calorimeter response to protons and anti-protons here in Sydney. In this project, you will use this new information to design a better, more sensitive p pbar decay search for the Belle II experiment.

Theoretical Physics

Title of Project: Hunting for dark matter at the LHC within unitarised effective field theories

Supervisor: A/Prof Archil Kobakhidze, Dr Michael Schmidt

Co-supervisor:


The experimental search for dark matter particles is one of the main scientific priorities of the physics program at the Large Hadron Collider (LHC). Effective field theory (EFT) is the most convenient theoretical framework for model-independent interpretation of the experimental data on dark matter. However, its direct application to experiments at high energies is plagued with serious theoretical problems, such as violation of perturbative unitarity. Hence, the use of EFT for interpreting the LHC data is limited. Recently we have suggested a new framework of unitarised EFT, which is free of the above-mentioned theoretical inconsistencies. The aim of this project is to expand the unitarised EFT formalism and apply it to the analysis of the latest dark matter data from the LHC.




Title of Project: Monopoles in Born-Infeld extension of the Standard Model

Supervisor: A/Prof Archil Kobakhidze

Co-supervisor:

Email Contact: [email protected] Brief Description of Project or Project Area: Monopoles are hypothetical particles that carry magnetic charge. They have been theorised by Paul Dirac in 1931, but have not been observed yet. There are ongoing experiments at the Large Hadron Collider (LHC) specifically dedicated to searches for massive monopoles. In this project, we study new type of electroweak monopoles within the Born-Infeld extension of the Standard Model, motivated by fundamental string theory. Prospects of their detection at LHC will also be investigated.

Title of Project: Exploring new physics with gravitational waves

Supervisor: A/Prof Archil Kobakhidze

Co-supervisor:

Email Contact: [email protected] Brief Description of Project or Project Area: The recent direct observation of gravitational waves by LIGO Collaboration opens new opportunities to explore fundamental physical phenomena at microscopic scales. In this project, we will calculate corrections to the standard gravitational waveform from the inspiral of two massive black holes within the extension of General Relativity by higher curvature terms. Such additional terms typically arise in the fundamental string theory. Theoretical calculations will be confronted with the observed waveforms with the aim to obtain empirical constraints on the string scale.




Research Projects in Photonics and Optical Science

Title of Project: How to get nonlinear vacuum

Supervisor: Prof Martijn de Sterke

Dr Andrea Blanco Redondo and Dr Alessio Stefani

Email Contact: [email protected], [email protected]


In nonlinear optics, the refractive index of a medium depends on the light intensity. However, media that are nonlinear are also dispersive, i.e. the refractive index also depends on wavelength. So these effects are always studied in combination. Now vacuum is unique in that it has no dispersion (the fact that n=1 is less important), but it also has no nonlinearity! In this project, we are after waves that are nonlinear but have no or little dispersion—the investigation of such light waves, which in a sense behave like nonlinear vacuum, is exciting and wide open. Achieving such waves requires two large effects, due to the material and due to the electromagnetic environment, here a fibre, to cancel, and requires the development of a systematic approach. In this computational project, which mostly uses existing software, you will design a fibre with such properties. If the design looks promising, it will be fabricated by our collaborators in Germany. We can then turn to the experimental study of how light propagates through nonlinear vacuum!

Title of Project: High-energy femtosecond lasers

Supervisor: Dr Andrea Blanco-Redondo

Co-supervisor: Prof Martijn de Sterke



Ultrafast lasers – light sources emitting pulses shorter than 1 ps – have been at an impasse for 20 years. This is impeding progress in science, where ultrafast lasers are a widely-used research tool - thanks to the huge achievable intensities up to petawatts per centimeter. And, more importantly, it is limiting their widespread use in fields of great societal impact, such as in laser surgery and materials processing. Since the impasse is inherent in the current technology it can only be solved with new physics, and we have the key to do so! Based on our recent discovery of the pure-quartic soliton (PQS), a novel class of solitary optical wave that does not disperse and behaves like a particle, we will create an innovative ultrafast fibre laser combining simplicity, efficiency and high power levels. The first step of this experimental project is to demonstrate the existence of PQSs in a specialty platform (microstructured optical fibers) that can support ultrahigh energies. The next step will be experimentally demonstrating the novel energy scaling law of PQS. After that we will be in the position to build the first PQS laser!






Title of Project: Optical Event Horizon

Supervisor: Dr Andrea Blanco-Redondo

Co-supervisor: Prof Martijn de Sterke and Prof Joss Bland-Hawthorn



Imagine we could simulate an event horizon in the lab… Stop imagining and start working on it! The physics of the event horizon are actually analogous to the behaviour of waves in moving media. In our lab we can engineer and test light waves that have the same dynamics. This relies on a special type of waveguide through which different colours (i.e. wavelengths) travel at dramatically different speeds. Since a high-intensity ultrashort optical pulse effectively changes the medium in which it propagates, we are in effect creating a moving medium. A weaker optical wave propagating much slower feels the effects of this moving medium. Indeed, the weaker optical wave can never penetrate the spatio-temporal region occupied by the intense pulse. Does it sound familiar? We have created a white hole, a region of spacetime that cannot be entered from the outside! This experimental project involves optical characterization of the nanophotonics platform and realisation of the optical white hole experiment. These experimental results will be directly applicable to future studies of the quantum effects of event horizons, including Hawking radiation.

Title of Project: Pure quartic solitons - excitation and propagation


Co-supervisor: Dr Tristram Alexander


The discovery of solitons revolutionised our understanding of wave dynamics. The conceptual leap was the realisation that nonlinear (i.e., intensity-dependent) effects, leads to completely new phenomena if they can be made to balance the linear properties. In optics, increasingly complex nonlinear phenomena have been explored with the aim to uncover new behaviour, with novel sensing, information transfer and optical processing applications emerging on the back of this work. But in all of this, across all fields of soliton physics, the linear part of the problem has remained unchanged. This is with good reason—the effect of nonlinearity can be seen just by increasing the intensity of a wave, but changing the linear properties is much more subtle. However, this has now become possible: very recently, in a carefully constructed waveguide, a completely new type of soliton was observed. The nature of these “pure quartic solitons” is largely unknown. This project seeks to go beyond the decades-old paradigm of soliton physics to develop the theory of solitons originating due to the interplay of nonlinearity and dispersion of high-order. Preliminary work has revealed that these solitons have unusual properties, demonstrating long-term non-equilibrium dynamics. This theoretical and numerical project will develop this theory, identifying the form of these nonlinear waves, their stability and the origin of the unusual excitations observed in experiment.

Title of Project: Harnessing energy at the microscale







Co-supervisor:


Extracting work from heat at the microscale is at the centre of numerous thought experiments exploring the concepts of thermodynamics, including famous examples such as the Feynman ratchet and Maxwell's demon. The underlying requirement made clear by these thought experiments is that there must be heat baths at different temperatures for work to be done. At the microscale, maintaining this thermal gradient is difficult, but could be achieved for instance by the presence of a "thermal diode". Diode-type effects are familiar in optics and electronics, but are proving to be an outstanding challenge in the context of thermal vibrations. This project will examine the conditions for targeted energy transfer at the microscale, including identifying the essential components required to achieve non-reciprocal energy flow through a thermal diode. The ultimate goal is a theoretical demonstration of one-way vibrational energy transfer without external control.

Title of Project: Ease the squeeze: concentrating light to the nano-scale


Dr Alessandro Tuniz and Dr Stefano Palomba


Squeezing light to volumes that are much smaller than the wavelength (say, 10x10x10 nm3) is a challenging but exciting prospect, since it forces the light to interact very strongly with its environment - the strong nonlinear effects that arise in such extremely small volumes lead to very sensitive bio-sensing, efficient wavelength conversion, and quantum-dot-excitation. The key problem is getting light into the volume to begin with —simply aiming a light beam at it is dreadfully inefficient, no matter how tightly you focus it. One way to achieve this, which has so far been overlooked, is through an adiabatic coupler: light starts in a conventional waveguide, which is gradually shrunk, forcing the light to a nearby guide, which can be arbitrarily small. While this sounds easy in principle, it has yet to be achieved in practice - the theory has been developed for lossless structures, but not for structures with losses, which are required to achieve tight squeezing. This project combines pen-and-paper theory with numerical calculations using state-of-the-art simulation software. The results will have very important consequences in a number of fields, including nonlinear optics, bio-sensing, and quantum photonics. The designed nanostructures will be fabricated at the Australian Institute for Nanoscale Science and Technology, and optically characterized at the Nanophotonics and Plasmonics Advancement Lab.





Title of Project: Single-molecule Raman spectroscopy in a photonic chip

Supervisor: Dr Stefano Palomba, Dr. Alessandro Tuniz and Prof. Martijn de Sterke

Co-supervisor:

Email Contact: [email protected], [email protected], [email protected] Brief Description of Project or Project Area:

The demand for efficient diagnostic tools in medicine, biology and environmental sciences has in common the need for detecting low concentrations of molecules in real time. Raman spectroscopy is a popular diagnostics tool which can in principle detect even single molecules; however, typical signals are too weak for

single-molecule applications. It is now well known that Raman signals dramatically increase when molecules are located on gold or silver nanostructures; however, the techniques used to achieve this are incompatible with universal integrated photonic sensors. We aim to overcome this limit by designing and engineering an integrated photonic-chip nanofocusing device which can generate high field intensities and induce large Raman signals in a fluid channel that is only 10’s of nanometers wide, so that we can optically detect single molecules when they enter this channel. PROPOSED WORK: This project aims to design a photonic sensor compatible with nanofluidic systems which can achieve large field intensities for Raman excitation and detection and paves the way for an on-chip plug-and-play devices for use, for example in mobile phones.





Title of Project: Graphene nonlinear plasmonic: next generation of nanostructured nonlinear optical devices

Supervisor: Dr Stefano Palomba

Co-supervisor: Dr Alessandro Tuniz, Prof Martijn de Sterke


Graphene is one of the most studied 2D materials to date, with astonishing and unique properties. It is constituted by only one layer of carbon atoms, which is the fundamental building block of various allotropes, such as graphite and carbon nanotubes. Due to graphene’s unique electronic, mechanical, optical and thermal properties, it has been extensively investigated theoretically and experimentally, ever since it was first discovered in 2004. Graphene is found to

exhibit remarkable nonlinear optical properties and tunable band structure. On the other side, it is well known that metallic structures, such as metal-dielectric-metal (MDM), can enormously enhance the optical field in the dielectric at very small gaps between the two metals (5-10nm). Hence, combining the outstanding nonlinear optical properties of graphene with the high enhancement generated by the MDM configuration will strongly and efficiently generate nonlinear phenomena. Such nanostructures could be the building blocks for generating high nonlinearities on-chip, which are important for communication, wavelength conversion, quantum information processing, etc. PROPOSED WORK: This is an experimental project in which the metal-graphene-metal nanostructures will be tested and characterized by measuring a certain nonlinear phenomenon (four-wave-mixing) in the Nanophotonics and Plasmonics Advancement Lab (NPAL).



Title of Project: Hybrid plasmon-acoustic surface waves: waves at the extremes of nonlinear optics


Co-supervisor: A/Prof. Christopher Poulton, Dr Birgit Stiller, Dr Alessandro Tuniz and Prof. Benjamin J. Eggleton


Gold and silver are extraordinary photonic materials, since they can support tightly confined optical waves at their boundary, which possess large optical nonlinearities. These surface waves – known as surface plasmon polaritons - offer a unique bridge between optics and electronics. Additionally, mechanical waves can also travel along these edges – they are known as Rayleigh waves, and often arise in earthquakes. At very high frequencies and on the nanoscale, these two types of waves

can interact, creating a new optical nonlinearity that can be used for a range of breakthrough applications in sensing, filters, and nanolasers. This is a recently proposed interaction, the physics of which has not yet been explored. PROPOSED WORK: This project will investigate new types of nonlinear hybrid plasmon-acoustic waves for the first time, both in metallic films and waveguides. The theory developed will lead to experiments on structures to be fabricated at the Australian Institute for Nanoscale Science and Technology (AINST) and to be tested in the CUDOS and NPAL labs. The project will suit a student with an interest in theoretical or wave physics, strong mathematical skills, and strong interest in programming and/or experimental physics.



Title of Project: Silk photonics: a biocompatible platform for biophotonics on-chip


Co-supervisor:


The population wellbeing and health, the environmental monitoring, nutrition regulations and early disease diagnostics have as common denominator the low concentration detection capability, often at the single molecule level, of the active molecules of interest in real time, with portable and reliable devices. Traditional techniques are time consuming, expensive, not portable and need highly technical and laborious sample preparation. Hence it is imperative the

development of fast, compact, self-sufficient, accurate and cost-effective Lab-on-a-Chips (LOC), which are capable of performing all the required functionalities. One of the most important components of a LOC system is always the sensor, which can be optical. Most of the integrated optical sensors are based on using evanescent field to detect the molecule of interest, which can be by fluorescence or by index of refraction variation, like in microring or microsphere resonators. These are based on inducing whispering gallery modes into the sphere by appropriately coupling light and detecting the change in resonance due to the interaction between a biomolecule and the sphere. Recently one of our collaborators was able to prepare silk microspheres; silk is a fully biocompatible and photonic material. PROPOSED WORK: This project is experimental and aims to test and improve the optical setup we developed for characterizing such microspheres in terms of their performances. This work on the dedicated setup will be performed in the Nanophotonics and Plasmonics Advancement Lab (NPAL).

Title of Project: QUANTUM PHOTONICS AT THE NANOSCALE


Co-supervisor:


Brief Description of Project or Project Area (5 – 10 lines long):

Nanophotonics is currently one of the most promising platforms for quantum information processing. It can be used in two different directions: 1. to generated single photons on demand which are the fundamental building block of any photonic quantum chip that uses linear optical element to implement quantum algorithms on chip; 2. to generate nonlinear phenomena, like cross-phase modulation, which could be used to perform a - the keystone of any quantum information processing.

PROPOSED WORK: This project aims to experimentally explore viable setup configurations, like the Sagnac interferometer, in order to perform such quantum nanophotonics experiments of nanostructures and integrated nanophotonics devices. This work will be performed in the Nanophotonics and Plasmonics Advancement Lab (NPAL).




Title of Project: GRAPHENE NANORIBBONS: A REVOLUTION IN 2D SENSING


Co-supervisor:



Currently surfaces plasmons (SPs), which are coherent oscillation of electrons at the metal-dielectric interface, are the cornerstone of applications that spans from ultrasensitive optical biosensing, photonic metamaterials, light harvesting, optical nanoantennas, and quantum information processing. However, metals are very lossy, i.e dissipate a lot of energy; this limits enormously their applicability as optical processing devices. In this context, electrically doped and nanostructured graphene emerges as an alternative. This atomically thick sheet of carbon atoms exhibits a SP in the far infrared. However, in case of nanostructuring graphene as nanoribbon, and in case of electrically doping it in a transistor-like configuration, it is possible to shift the SP resonance toward the more useful near infrared and even visible spectrum region. This can

become a very efficient 2D sensor. PROPOSED WORK: This project aims to electrically and optically measure the properties of such electrically doped nanoribbons. The measurements are going to be done in the Nanophotonics and Plasmonics Advancement Lab (NPAL).

Title of Project: Quantum biology: a promising route for ~100% efficient light harvesting


Co-supervisor: Prof Zdenka Kuncic, Prof Min Chen


Recent discoveries suggest that coherent quantum processes might be found in Nature at room temperature and in living organisms. One example resides in robins’ ability to navigate using Earth’s magnetic field; another one might resides in the still today elusive inner mechanisms of photosynthesis, which is the process by which plants and bacteria turn sunlight into chemical energy for their survival. These photosynthetic organisms have evolved light harvesting complexes for this function, with very high light-

conversion efficiency (>95%). Here, at the University of Sydney, Prof Min Chen has extracted and characterized a novel light harvesting complex from an Australian species, which is still understudied. PROPOSED WORKED: This project aims to experimentally investigate the light-harvesting characteristic of this novel chlorophyll complex at single molecule level, and its subsequent quantum-related properties.




Title of Project: Hybrid plasmonic microresonators for on-a-chip bionanophotonic sensors

Supervisor: Dr Stefano Palomba, Dr Alessandro Tuniz and Prof Martijn de Sterke

Co-supervisor:

Email Contact: [email protected], [email protected], [email protected] Brief Description of Project or Project Area:

Optical micro-resonators can be used as excellent sensors for lab-on-a-chip devices; however, they are commonly made of glass or silicon, where light-matter-interactions are very weak, and which are not bio-compatible. To address the first issue, it has been shown that, nanostructured metals can enormously compress light and give rise to huge light intensities via so-called plasmonic enhancement, at the cost of some additional loss. To address the second issue, silk has recently emerged as a promising photonic

platform which is also bio-compatible. In this project, we wish to produce a micro-resonator which “combines the best of all worlds”: by merging metals and dielectrics into a silk-based photonic structure, we can obtain extremely high light intensities with moderate losses, on a convenient bio-compatible platform. PROPOSED WORK: This project will look at accurately modelling the coupling between silk resonators and plasmonic antennae; we will use a recently developed theoretical framework to design a dielectric resonator which couples to a plasmonic antenna and give rise to enhanced light-matter interactions. This design will be lead to the fabrication of these nanostructures and be complemented by the development of an experimental setup to characterize them with our in-house facilities at the Australian Institute for Nanoscale Science and Technology (AINST) and the Nanophotonics and Plasmonics Advancement Lab (NPAL).

S. Holler et al., Proc. SPIE 8722, Fiber Optic Sensors and Applications X, 2013





Title of Project: Neuromorphic photonics: an all-optical brain on-a-chip for enhanced computing

Supervisor: Prof Benjamin Eggleton

Co-supervisor: Dr Stefano Palomba

Email Contact: [email protected] ; [email protected] Brief Description of Project or Project Area:

Information processing is the fuel of modern society. This is currently based on electronic-based information processors which are at an impasse due to the almost unbearable power consumption per flop of information. Looking at Nature, our brain is capable of processing and executing much more complex tasks with orders of magnitude less power (only 20W). Photonic integrated systems that are isomorphic to biological neural network (i.e. brain-like or neuromorphic

photonic systems) can unlock the wealth of fast, intelligent and low power consumption processor, becoming the fundamental building block for any future Artificial Intelligent system, capable of human-like tasks. PROPOSED WORK: This project envisions a thorough literature review on neuromorphic photonic systems and a subsequent new platform design based on our expertise on nonlinear optical integrated devices. Indeed, it is currently clear that the bottleneck of these systems is mainly dictated by developing an appropriate nonlinear optical system. This first part could be followed by preliminary experimental tests for a proof of principle. This work will pave the path toward the development of a revolutionary technological leap heading for the implementation of a fully “neuromorphic” computer.

Title of Project: Highly nonlinear gold nanowires in optical fibres

Supervisor: Dr Alessandro Tuniz

Co-supervisors: Prof Martijn de Sterke, Dr Stefano Palomba

Email Contact: [email protected]; [email protected]; [email protected], Brief Description of Project or Project Area: The large nonlinear optical response of gold has far-reaching applications, and will play an important role in next-generation photonic chips, where gold be used to compress light to the nanoscale. However, gold’s nonlinearity is still not completely understood: a survey of the literature suggests that it varies by orders of magnitude depending on pulse duration, but a systematic and consistent study is lacking. At the same time, a new geometry has emerged to study this: a step-index fibre with a gold-nanowire in its core, which possesses a large nonlinear response. This project aims to develop a theoretical framework predicting the nonlinear response of these gold nanowires at different wavelengths and pulse durations, and verify these results experimentally in the Nanophotonics and Plasmonics Advancement Lab (NPAL). This project is suited for those interested in both numerical modelling and experimental physics.

Prucnal, P. R., Shastri B. J., Neurommorphic Photonics, 2017







Title of Project: Metamaterials with a twist

Supervisors: Dr Alessandro Tuniz, Dr Alessio Stefani

Co-supervisor: Prof Simon Fleming

Email Contact: [email protected]; [email protected]; [email protected] Brief Description of Project or Project Area: Over the past decade, metamaterials have brought incredible new regimes to the optical landscape, from invisibility and cloaking, to deep-sub-wavelength imaging. In recent years, our group has pioneered a method to make these metamaterials in fibres, which typically contain very small metal wires or resonators. However, these fibres are static: for a given sample, you simply use it with its designed optical properties. Last year, we found a way to make a very flexible fibre, which can be twisted and deformed at will, and returned to its original state. This opens up new opportunities for turning electrical wires into magnetic resonators by twisting, paving the way for a new generation of tuneable metamaterials. In this project we aim to design, fabricate, and characterize tuneable and flexible metamaterials with extraordinary electromagnetic properties. You will develop a simple pen-and-paper theory for the resonant properties of these twisted metamaterials, use commercially available simulation software for the final design, make the fibres using our in-house fibre draw tower, and experimentally characterize them using our setup.

Title of Project: Efficient Terahertz Near-Field Nano-Probes

Supervisors: Dr Alessandro Tuniz

Co-supervisors: Dr. Alessio Stefani, A/Prof. Boris Kuhlmey

Email Contact: [email protected]; [email protected] Brief Description of Project or Project Area: Terahertz imaging uses millimetre waves for a wide variety of diagnostics applications, including biomedicine, security and quality control. Fast, robust, reliable, and efficient terahertz antennas are however lacking, especially on the nano-scale. In recent years, we have been developing a new approach of manipulating terahertz radiation using metallic micro- and nano-wires integrated inside optical fibres. On the basis of this platform, this project will design high-efficiency nano-antennas for detecting THz-radiation with nanoscale resolution, to be integrated into commercial systems, using analytical tools and commercial software. The designed structures will be fabricated either at the Australian Institute for Nanoscale Science and Technology, or at our fibre draw tower, and optically characterized in our laboratory.







Title of Project: Energy exchange up close

Supervisor: A/Prof Boris Kuhlmey

Co-supervisor: Prof. Martijn de Sterke



Consider an atom in an excited state and an identical one, for away, in the ground state: the atoms can exchange energy through a photon. Förster resonant energy transfer (FRET) is the process which occurs when the distance between the atoms is a few nanometers. The energy exchange is now dominated by a process which is non-radiative and which decays as r-6. FRET is not only a phenomenon of fundamental importance in physics, but, through the steep r-6

dependence, can also be the basis of imaging devices. Its dependence on orientation of molecules and electromagnetic environment is difficult to study in optics, but strong analogies exist with the interaction between antennas at lower frequencies–microwaves or terahertz (THz) radiation, where orientation and environment are easily controlled. The application to THz radiation is particularly intriguing as THz spectroscopy can provide information on large scale molecular structures but is strongly limited by the diffraction limit when using far field optics. This project will explore THz equivalence to FRET equivalent to study the effect of the electromagnetic environment between acceptor and donor, and how these effects can be harnessed for THz spectroscopy at the micro or even nanoscale. It can be theoretical, numerical, experimental, or a combination of these.

Title of Project: Selective modal excitation in multicore fibres with optical fibre couplers




Multicore Fibre (MCF) is a revolutionary new approach to engineer a fibre for high capacity communications and applications in several research areas from sensing to astronomy. MCFs used in conjunction with photonic lanterns, are now enabling an even bigger leap towards multimode photonics. Until recently, the single-moded cores in MCFs were not sufficiently uniform to achieve telecom performance. Now that high-quality MCFs have been realized, we turn our attention to achieving complex functions with them, from sensing to filtering. This project will study for the first time hybrid optical fibre couplers between MCFs and single-core fibres to realise selective excitation of higher order modes of propagation in the cores of the MCFs. The demonstration of those complex optical waveguide composite systems will open the gate to a new way to produce multicore fibre devices that could be used in laser, communication and optical sensing systems. This project will have theoretical and experimental parts with the flexibility to focus in either of the two, depending on student preference.





Title of Project: All-fibre adaptive optic system for optical beam shaping


Co-supervisor: Dr Chris Betters/Barnaby Norris

Email Contact: [email protected] Brief Description of Project or Project Area: Photonic lanterns- efficient multimode to single-mode convertors devices are a very fascinating technology currently used in Astronomy and Telecommunications. Those optical devices convert light from a set of co-propagating optical modes with different spatial electromagnetic distributions into a set of identical optical modes at different fibre ports and vice versa. The unique properties of photonic lanterns also enable dynamic control of the beam intensity and phase, which has enormous potential for advanced high speed adaptive optics beam shaping. This project will study an alternative approach to spatial-mode control using active feedback to stabilize and shape the output beam of a multimode fibre by appropriately launching the correct superposition of input modes in both phase and amplitude. Hence, achieving an all-fibre based AO system that preconditions the input to achieve a desired beam shape and phase on the output.

Title of Project: Vibrations in silicon

Supervisor: Dr. Alvaro Casas Bedoya and Dr. Amol Choudhary

Co-supervisor: Prof. Benjamin Eggleton



Strong light beams can literally shake the material at the nanoscale. These vibrations result in hypersound which can be harnessed for several exotic applications on a photonic circuit. Silicon is the most widely used electronic platform and was the basis of the electronics revolution of the 20th century. A multi-trillion dollar industry is based on this material and we are moving towards the next revolution: a photonic-phononic revolution! In this project, we will explore the development of optical and phononic circuits in silicon. There will be opportunities to model and design photonic-phononic circuits in this project. The state-of-the art cleanrooms at the Sydney nanoscience hub will allow the student to fabricate their own devices and test them in our labs at CUDOS. At the end of the project, the first ever circuit with both photonic and phononic components will be demonstrated. This will be a crucial step towards the long-term vision of integrating photonic-phononic circuits with electronics on a single chip.




Title of Project: Miniaturized Photonic Chip, Optical Signal RF Spectrum Analyser

Supervisor: Mark Pelusi

Co-supervisor: Alvaro Casas Bedoya, Ben Eggleton



The RF spectrum is a powerful diagnostic tool for characterizing the fast, time varying waveforms of signals. Its measurement has been shown possible in the optical domain by propagation through a waveguide, where the signal mixes nonlinearly with another propagating field at different frequency, to create the RF spectrum that is measurable by standard optical spectrum analysis. This approach has the advantage of enabling an ultra-wide measurement bandwidth (beyond 1 Terahertz) that far exceeds the capability of state of the art, high speed opto-electronics. This project will investigate the world’s first, fully integrated chip “all-optical” RF spectrum analyser, based on an in-house designed, photonic integrated circuit that has recently been fabricated in silicon, and aim to demonstrate its capability for broadband RF spectrum analysis of high speed optical signals.

Title of Project: Broadband Optical Frequency Combs for High Speed Internet


Co-supervisor: Ben Eggleton



Optical frequency combs have wide-ranging applications in astronomy, meteorology, and medical imaging to bio-sensing, and more recently, for optical communications, by enabling a single laser source to carry hundreds of data channels on different frequencies, in place of the hundreds of single frequency laser modules used in today's multi-Terabit/s systems. This can enable more energy efficient, higher speed internet. This project will investigate generating low noise, broadband optical frequency combs for carrying higher bit rate signals, and aim towards a laboratory demonstration of a laser source capable of carrying over one hundred times more information capacity than a conventional single frequency laser.

Title of Project: Overcoming the Optical Nonlinear Shannon Limit for High-Speed Communications


Co-supervisor: Ben Eggleton



The Nonlinear Shannon Limit is a fundamental bottleneck to the growth of the internet, and originates from the Kerr effect in optical fibre inducing a refractive index change in proportion to the light intensity propagating through it. The fast effect, responding on a femtosecond time-scale, is complicated by optical intensity noise and the fibre’s chromatic dispersion, making its full compensation in real communication systems near impossible. This project will explore novel optical signal processing techniques that can manipulate the phase of data carrying photons to better suppress the induced signal distortion, and aim towards a laboratory demonstration of the device enabling record-breaking long distance transmission of high bit rate optical signals in optical fibre.





Title of Project: Mastering vibrations in Graphene

Supervisor: Dr Birgit Stiller, Dr. Amol Choudhary and Prof. Benjamin J. Eggleton

Co-supervisor:



A single-atomic-layer graphene was extracted for the first time in 2004 for which the 2010 Nobel Prize in physics was awarded. Since then it has been branded as the ‘wonder material’ and has attracted the interest of researchers worldwide due to its unique properties in mechanics, optics, electronics and other domains. Various applications such as super-strong materials, solar cells and new electronic devices prove the high relevance of this material. In this project, you will investigate acoustic waves travelling through the thin Graphene layers with help of stimulated Brillouin scattering (SBS), which is one of the strongest non-linear interactions known to date. The latter is an acousto-optic interaction that leads to forward and backward light scattering in optical waveguides. You will take advantage of our expertise of integrated non-linear optics at CUDOS in order to test the influence of Graphene on top of chalcogenide and silicon waveguides.

Title of Project: Sound waves in silk

Supervisor: Dr Birgit Stiller and Prof. Benjamin J. Eggleton

Co-supervisor:



The ancient material silk is recently making a splash in the scientific community due to its unprecedented properties for technological applications. Silk is fully bio-compatible, bio-degradable and edible. With the ability to pattern silk - down to the nanoscale - and form devices researchers were able to find new ways to e.g. deliver drugs into the human body or sense diseases inside the body by harnessing the optical properties of silk. However, the superior mechanical properties of silk just recently came to researchers’ attention, reporting for the first time high frequency (several GHz) acoustic phonons in silk. The group of Prof. Benjamin Eggleton is at the forefront of studying the interaction of acoustic phonons and photons in waveguides. The techniques pioneered over the years here at the school of physics can be used to investigate the mechanical properties of silk waveguides and provide a deeper understanding of this truly beautiful material.




Title of Project: Golden tunes: Light and sound in plasmonic nanostructures

Supervisor: Dr Birgit Stiller and Dr Alessandro Tuniz

Co-supervisor: A/Prof. Christopher Poulton, Dr Stefano Palomba , Prof. Benjamin J. Eggleton



Light and sound will complement electronics within next-generation photonic-chips, to address imminent technological bottlenecks using a single low-footprint device. Recently, it has been shown that the interaction of light and sound (so-called Stimulated Brillouin Scattering) is a powerful tool for on-chip optical manipulation, enabling ground-breaking applications in telecommunication, optical memory, and all-optical signal processing. On the other hand, these interactions still require large input powers and centimetre-length devices. One way to circumvent this is by using gold and silver nanostructures: by coupling light to electrons (via so-called Plasmonic interactions) we can achieve extremely large optical confinement (down to the nanometer scale).

In this project, we will merge the fields of Stimulated Brillouin Scattering and Plasmonics for the first time, by investigating how opto-acoustic interactions on gold nanostructures will play a role in next-generation photonic chips. The project will involve numerical modelling of structures to be made at the new Australian Institute for Nanoscale Science and Technology (AINST).


Research Projects in Physics Education

Title of Project: The measure of things

Supervisor: Tom Gordon

Co-supervisor: Prof Manjula Sharma


In this project, you will compare different measurement devices against the Measurement capabilities of a smart phone or tablet device. You will compare the reliability, validity and accuracy of these devices against common measurement devices used in the laboratory environment either at secondary or tertiary settings. This project is suited to those interested in education and engagement in Physics. The project may also include development and integration of measurement devices, applications and techniques. This project is part of a government funded project on improving school science. The findings from these projects are being used in workshops with school teachers and students across the country, from Darwin to Armidale. They have the potential to be published in journals.

Title of Project: Science inquiry: From demos, recipes to open investigations

Supervisor: Prof Manjula Sharma

Co-supervisor: Tom Gordon


The Australian Government has funded a $2M national project to improve school science education by researching ‘how to make better use of investigations’ to engage and excite students as well as improve understanding. Your project will entail examining issues ranging from:

• How often are investigations used?

• What is the nature of investigations carried out in school classrooms?

• Developing and evaluating experiments.

• Involvement in workshops across the country.

• Many other questions you can design The findings from this project will being used in workshops with school teachers and students across the country, from Darwin to Armidale. They have the potential to be published in journals.

Title of Project: Topic of your choice

Supervisor: Prof Manjula Sharma

Co-supervisor: Tom Gordon


The Sydney University Physics Education Research (SUPER) group can and does undertake projects on topics ranging from misconceptions, multiple representations, different ways of teaching to use of multimedia for teaching physics. Please contact us and we will work with you in finding the right project for you. Check out our website for possible topics to investigate.





Research Projects in Quantum Physics and Quantum Information

Title of Project: Numerical methods for simulating quantum spin lattices

Supervisor: Prof Stephen Bartlett

Co-supervisor: A/Prof Andrew Doherty and/or Dr Steve Flammia


Brief Description of Project or Project Area: Quantum spin lattice models (models of many quantum spins) are of immense interest in the condensed matter and quantum physics communities. These models exhibit extremely unusual (topological) collective quantum properties, making them promising candidates for quantum computation. Analytical and experimental investigations of these models are the subject of much research in the Quantum Science group. Numerical simulations complement and expand our analytical understanding of these models, as well as provide evidence of experimental signatures that are observable in the lab. These simulations are extremely challenging to design (such that they effectively capture the quantum physics) and execute (such that they are feasible within current computing capabilities). The numerical methods used are state-of-the-art algorithms and are themselves under continual development, in order to better capture the quantum behaviour of many-body spin systems. This project would involve development of established numerical methods as well as theoretical many-body physics research. This project would suit a student with a programming/computer science background or inclination, as well as someone with an interest in many-body quantum physics. The numerical investigation would make use of MATLAB, C++ or python programming. The project may involve collaboration with or supervision of other members of the Quantum Science group.

Title of Project: Theory of quantum computing using electron spins in semiconductor nanostructures


Co-supervisor: A/Prof Andrew Doherty


The spin of a single electron can serve as a quantum bit or ’qubit’ – the basic element of a quantum computer – provided we can trap it in place, manipulate it, and cause it to interact with other spins in a relatively noiseless environment. Electrostatically-defined quantum dots in a two-dimensional electron gas in a semiconductor provides a way to do this, and is being pursued by the experimental group of Prof David Reilly as well as our collaborators at Copenhagen, Harvard, Tokyo, and elsewhere. We are offering a number of theory projects in this area including: (1) developing robust and efficient methods to compute the wave function of the electron, and how well the ‘quantum logic gates’ can be performed, based on electronic measurements; (2) understanding how the electron interacts with the nuclear spins in the semiconductor, with a specific aim to ‘programming’ the nuclear environment to interact with the electron in a specific way; (3) developing methods for quantum control of the electron; (4) designing basic demonstrations for quantum algorithms to run on a simple quantum computer. These projects can involve a mix of analytical mathematical methods as well as numerics (Matlab).




Title of Project: Manipulating anyonic defects in two- and three-dimensional topological models


Co-supervisor: Dr Steve Flammia


Brief Description of Project or Project Area :

A topological model is a quantum many-body system with a ground state degeneracy that depends on the topological properties of the lattice in which it is defined. Defects in these models can behave as anyonic degrees of freedom – they don’t act as either bosons or fermions, but acquire more general phases when braided around each other. Such anyonic degrees of freedom as defects can encode quantum information, and we can perform operations on this information by braiding the defects through a process called code deformation. In addition, code deformation allows us to change the types of anyons and even the dimensionality of the system (eg move from 2D to 3D in a local patch). We will investigate how code deformation can perform interesting quantum operations in a specific set of models known as colour codes.

Title of Project: Ion Trapping Hardware for Quantum Control

Supervisor: Prof Michael J. Biercuk

Co-supervisor:

Email Contact: [email protected] Brief Description of Project or Project Area: The Quantum Control Laboratory is an experimental research group focused on the control and manipulation of the internal states of trapped ions as model quantum systems. This project will focus on the development of new ion trapping hardware specially suited to these experiments, incorporating high optical access and access for microwave antennae used to control the ion spin state. The student will have the opportunity see the development of new experimental infrastructure from the ground up, including the development of high-stability laser systems, microwave and radiofrequency electronics, and ultra-high vacuum systems. This project will be conducted within the new Sydney Nanoscience Hub.

Title of Project: Advanced Digital Hardware for Quantum Control


Co-supervisor:


The Quantum Control Laboratory is an experimental research group focused on the control and manipulation of the internal states of trapped ions as model quantum systems. Experimental systems are extremely complex and require the synchronization of many disparate technical subsystems on nanosecond timescales. This project will focus on the development of highly customized digital electronics for applications in experimental control, laser stabilization, and the like. Efforts will be based on Field-Programmable Gate Arrays, and will require strong programming capabilities. This project will be conducted within the new Sydney Nanoscience Hub.





Title of Project: Quantum Control of Trapped Ytterbium Ions


Co-supervisor:


The Quantum Control Laboratory is an experimental research group focused on the control and manipulation of the internal states of trapped ions as model quantum systems. In particular, we are interested in studying new techniques to perform quantum logic operations in a manner that is robust against errors. This can be accomplished through the application of a special sequence of control operations designed to ``erase'' the buildup of error due to uncontrolled environmental coupling. The project will focus on the implementation of such control protocols using a special microwave system that permits arbitrary manipulation of a Ytterbium atom's quantum state. This project will be conducted within the new Sydney Nanoscience Hub. Experience gained in this project will cover atomic physics, magnetic resonance, microwave systems, and quantum control. Multiple projects are on offer within this heading.

Title of Project: Programmable Quantum Simulation in Ion Chains


Co-supervisor:


The Quantum Control Laboratory is an experimental research group focused on the control and manipulation of the internal states of trapped ions as model quantum systems. We have developed new experimental capabilities allowing the trapping and coherent manipulation of chains of ions in a RF Paul trap. We are seeking to leverage new theoretical concepts developed by our group in order to realize Programmable quantum simulators capable of investigating the physics of quantum magnetism in a well controlled experimental platform. This project will be conducted within the new Sydney Nanoscience Hub. Experience gained in this project will cover atomic physics, magnetic resonance, microwave systems, and quantum control. Multiple projects are on offer within this heading.




Title of Project: Large-Scale Quantum Simulation in a Penning trap


Co-supervisor:


Trapped atomic ions are a leading candidate system for experiments in quantum simulation, through which we attempt to realize a controllable quantum system capable of simulating more complex, uncontrolled quantum systems. This project will focus on the development of quantum simulation experiments using large ion crystals in a Penning trap. This effort will build on successful experimental demonstrations of quantum simulation using 300 qubits, and will leverage new insights into the control of quantum systems. This project will be conducted within the new Sydney Nanoscience Hub. This project will incorporate experience in experimental atomic physics, charged-particle trapping, custom experimental system design, and electromagnetic simulation. Multiple projects are on offer within this heading.

Title of Project: Quantum Control Theory for Robust Quantum Computation


Co-supervisor:


The Quantum Control Laboratory is a research group focused on the control and manipulation of the internal states of trapped ions as model quantum systems. Part of this research activity requires the development of new quantum control techniques via theoretical exploration. Our aim is to produce techniques which provide intrinsic robustness against errors - a major problem in quantum computation and quantum technologies broadly. This project will seek to develop and characterize the performance of efficient control techniques that suppress the effects of environmental decoherence and imprecise physical control systems. This project will be conducted within the new Sydney Nanoscience Hub. Through the project the student will learn quantum control, quantum information theory, and fundamental experimental aspects of quantum physics. Multiple projects are on offer within this heading.




Title of Project: Trilateration of quantum states

Supervisor: A/Prof Steve Flammia

Co-supervisor: Prof Stephen Bartlett



In a grand irony, the exact same exponential scaling that gives a quantum information processing device its power also limits our ability to characterize it. In short, an entirely new paradigm of “quantum learning” is required. The proposed research is to generalize and apply advanced methods from machine learning to develop efficient algorithms to characterize new devices that operate in the quantum regime. The aim of this project is to investigate some approaches to realize this new paradigm. We will generalize the idea of trilateration (used for GPS navigation) to the problem of estimating quantum states. To make this a scalable solution, we will require further to incorporate dimension reduction ideas from many-body (tensor networks, for example). A primary goal of the project is the implementation of the solution in the Python programming language.


Research Projects in Theoretical Physics


Theoretical Physics Group

Title of Project: Circular polarization and Faraday rotation

Supervisor: Don Melrose

Co-supervisor: Mike Wheatland


The radio emission from extragalactic radio sources is due to synchrotron emission which is partially linearly polarized. As radio waves propagate through the interstellar medium (ISM), the small difference in refractive index between left and right hand polarized waves causes the plane of linear polarization to rotate. The sign of this Faraday rotation depends on the sign of the projection, Bz, of the local magnetic field in the ISM on the ray path. Extragalactic sources typically also have a small degree of circular polarization, whose origin is uncertain. One model attributes the circular polarization to a propagation effect in the ISM, arising from the regions where Bz reverses sign. The project will involve integrating a matrix equation (for the Stokes parameters) along the ray path through an idealized model for the region where Bz changes sign. The predictions of the model will be compare with observational data. Melrose, D. B. & McPhedran, R. C. Electromagnetic processes in dispersive media. Cambridge University Press, 1991, p.189 Melrose, D.B. 2010, Faraday rotation: Effect of magnetic field reversals, Astrophys. J., 725, 1600


Research Projects in Theoretical Physics


Title of Project: Magnetar radiation belts




Magnetars are a class of pulsar-like neutron stars with exceptionally strong magnetic fields and slow rotation rates. They are observed primarily from their high-energy emission, in both Soft Gamma Repeaters (SGRs) and Anomalous X-ray Pulsars (AXPs). Outbursts on SGRs are the most powerful known examples of magnetic explosions. A subset of magnetars are also observed as radio pulsars. A favored model for the hard X-ray emission from magnetars involves high-energy pairs trapped in closed magnetic field lines (Beloborodov 2013). Such trapping is analogous to energetic particles trapped in the Earth's radiation belts, also known as the Van Allen belts (Luo & Melrose 2008). There is an extensive literature on how trapped particles are lost through precipitation into the Earth's atmosphere. This project will involve adapting models for the loss of trapped particles from the Earth's radiation belts to trapped relativistic particles in a magnetar magnetosphere. A specific question that will be addressed is: Do the trapped electrons and positrons precipitate, like the terrestrial analog, or do they slow down and annihilate in the magnetosphere? Observational implications of both possibilities will be explored. Beloborodov, A.M., 2013, On the mechanism of hard X-ray emission from magnetars, Astrophys. J., 762, 13 Luo, Q., Melrose, D.B., 2008, Pulsar transient radio emission, in Y.-F. Yuan, X.-D. Li, D. Lai (eds) Astrophysics of Compact Objects, AIP Conference Proceedings 968, p.159

Title of Project: Current starvation in pulsar magnetospheres




The electrodynamics of pulsars remains inadequately understood (Melrose & Yuen 2016). In a corotation model, the plasma around the neutron star is assumed to be rotating at the same angular velocity as the star. Corotating plasma implies a corotation electric field whose divergence implies a corotation charge density. “Charge starvation” refers to conditions under which the plasma cannot supply the required charge density, implying that the plasma cannot be corotating. In an oblique rotator, corotation also implies a corotation current density, and “current starvation” refers to conditions under which the plasma cannot supply the required current density (Melrose & Yuen 2016). Unlike charge starvation, the implications of current starvation for pulsar physics are yet to be explored. This project will involve reviewing pulsar electrodynamics, modelling the conditions under which current starvation is likely to be significant, and discussing possible observational consequences. Melrose, D.B., Yuen, R. 2016, Pulsar electrodynamics: an unsolved problem, J. Plasma Phys., 82, 635820202



projects available in 2018 - the university of sydney available in 2018 ... honours students are...

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