School of Physics and Astronomy
Funded Undergraduate Summer Placements 2015
The deadline for applications is 1pm on Wednesday 14th January.
Astrophysics
Observational studies of young stars
Professor Rene Oudmaijer
This project entails the analysis of state of the art optical and near-infrared data of young stars, with as main aim to understand the processes such as accretion that take place very close to the stars.
Massive Star Formation
Dr Stuart Lumsden
Analysis of observational massive star formation data.
The radiative overstability of dusty shocks
Dr Julian Pittard
Contact the supervisor for further information.
The effect of simplified physics on the results of numerical models
Dr Sven Van Loo
Often a physical process is included in a simplified way into a numerical code to improve the stability of a code or to get results faster. We will investigate the effect of one such simplification, e.g. cooling in the interstellar medium by comparing the simplified and full model.
Splash Landing – Dropping clouds onto galactic dishes
Professor Thomas Hartquist
Supernovae inject energy into the interstellar medium, which drives some of the material into the halo of the Galaxy.
A good fraction of this material cools and falls back to the disc. The encounter causes a splash, which may induce star formation. The project concerns the nature of the splash.
Condensed Matter
Readily kicked-off high frequency dynamics in chiral spin texture: for future non-volatile fast speed memory
Satoshi Sagomoto & Professor Chris Marrows
Modern society can be described as information society, thus faster and smaller memory device is pursued day-and-night. The idea of transferring spin texture as a unit of information carrier is enthusiastically discussed as a promising techniques for next-generation high density solid-state devices. Recently discovered chrial magnetic skyrmions are excellent candidates for a breakthrough in this challenge. Skyrmions are particle-like solutions of nonlinear equations that are observed in many physical contexts, such as Bose-Einstein condensates, the quantum Hall effect, and liquid crystals. Among them, magnetic skyrmions show great advantages in their scalability from conventional domain walls, and attract great attentions in terms of not only their academic interests but also applicational potentials.
This project is a part of comprehensive study of the fast speed dynamics of skyrmions and will suit a student with an interest in solid-state physics and experimental works. The participants are mainly expected to work with high frequency measurement system available at helium temperature, and aimed at experimental works on epilayers of FeCoSi and FeGe. This is newly established and developed with aiming at over 10 GHz frequency band at cryogenic circumstance, and contains many essences for microwave techniques and low temperature physics. In addition, students would also have opportunity to study series of basic apparatus necessary for solid state physics in Condensed Matter group, such as X-ray diffraction apparatus, Magneto optical Kerr microscopy, and so on.
Molecular spin capacitor
Dr Oscar Cespedes
Molecular films have low spin orbit coupling that leads to long spin coherence times. This makes them ideal for a novel device that would store not only electrical charge (i.e. electrons) but also spin information. This is an experimental project in which the student will be involved in the growth and magneto-electrical characterization of these devices -never before fabricated.
Spin coupling in topological insulators
Dr Oscar Cespedes
Topological insulators are a relatively new form of matter that is insulating in bulk but conducts in its surface. Due to time-reversal symmetry, only one electrons with one spin sign (say, up) can flow on the top surface, whereas the others (down) would flow on the bottom surface. These materials are therefore being explore as conductors and generators of pure spin currents that generate no or very little Joule heating. This is an experimental project and the student will be involved in preparing nm-thick flakes of TIs, growing magnetic thin films and doing characterization –including Raman spectroscopy and microwave irradiation.PureSpin Currents
Professor Brian Hickey
Quantum coherence (QC) is at the heart of many interesting phenomena in physics: superfluidity, superconductivity and of course Bose-Einstein condensation are examples of macroscopic quantum coherence where large numbers of particles can be described by a single wavefunction. QC also has interesting effects in electron transport, phase coherent scattering leads to localisation of electrons for example. Recently spin coherence has become a hot topic in spintronics. In this placement you will work in the team working on spin coherence in lithographically patterned structures. Pure spin currents carry a spin polarisation without transporting charge. This is achieved through equal numbers of charges moving in two directions polarised spin-up in one direction and spin-down in the other. The realisation of such a circuit can be demonstrated in this diagram[1]
Spin Hall Magnetoresistance
Professor Brian Hickey
Spintronics is a scientific pursuit that offers solutions to current technological problems such as the consumption of energy by electronics. Our research is aimed at exploring fundamental properties of electron transport that may have considerable advantages for electronics of the near future. For example, a pure spin current is the transfer of angular momentum (spin) without the simultaneous transfer of charge. This is accomplished by spin-up carriers moving in one direction while the spin-down carriers move in the opposite direction. Since the carriers differ only in their spin, no net charge is transported. This is an example of the transportation of information without dissipation through Joule heating. Spin currents are being explored for many purposes including lower energy-consuming electronics and as concentrations of angular momentum used to switch magnetic elements. Rotating a magnetic moment by transferring angular momentum from the electron system to the magnetic system achieves the desirable outcome of switching magnetic elements without applying a magnetic field. This effect is known as spin transfer torque.
The spin Hall magnetoresistance is the result of a spin current (Js), developed in a high spin-orbit material such as Pt or W, exerting a spin transfer torque on the magnetization of an adjacent material (panel e, below). The reflection from the magnetic interface causes a change in the spin current can affects the measured resistance of the normal metal (the lower layer).
Understanding the details of this effect is currently a very active area of research in spintronics. Theory predicts that the effect only depends on the orientation of the magnetization of the magnetic layer and that the magnitude of the effect is dominated by the spin Hall angle and the spin-mixing conductance. In recent measurements that we have made, it turns out that the simple picture will not explain the observations. It appears that the magnitude of the magnetization is important and that the temperature dependence although complicated, reveals many new details. This PhD project will continue the initial work we have completed and in conjunction with our theory collaborators, will reveal the fundamental properties of these spin effects. We will then be in a position to test the predictions on how to generate spin amplification and switching.
Figure taken from Nakayama et al PRL 110 206601 (2013)
"Unconventional Superconductivity Proximity Effects in Yttrium-Iron-Garnet/ Niobium / Co trilayers"
Supervisor G. Burnell with B.J. Hickey
Superconductivity and Magnetism are conventionally considered to be mutually antagonistic phenomena due to the competing electron spin ordering. Nevertheless, in suitably engineered systems involving non-colinear arrangements of ferromagnetic layers and low temperature superconductors, it is possible to generate superconducting states that show unconventional spin triplet states. In the condensed matter group we have been studying such systems, but until now, only useing ferromagnetic metals. At the same time we have developed the growth of YIG - a ferrimagnetic insulator and our theoretical collaborators have suggested that this two should be able to generate the spin triplet superconducting state, despite being an insulator. In this project the student will grow YIG and then Nb and Co layers on top and measure the critical temperature as a function of the relative angles of magnetisation between the Co and YIG layers to see if there is evidence of this spin triplet superconducting state.
Surface acoustic waves and magnetic domain walls
Dr Thomas Moore
Contact the supervisor for further information.
Chiral domain walls in ultrathin magnetic films
Dr Thomas Moore
Contact the supervisor for further information.
Periodically-driven topological phases
Dr Zlatko Papic – to be confirmed
Emergent non-Abelian quasiparticles in condensed matter
Dr Zlatko Papic – to be confirmed
Molecular and Nanoscale Physics
Patterning of Surfaces with Crystals -
Dr Hugo Christenson
We have shown how remarkable crystal patterns are created when thin films of sodium chloride solution are allowed to thin by evaporation and rupture on smooth surfaces like glass and mica (G. F. Harrington, J. M. Campbell and H. K. Christenson; “Crystal Patterns Created by Rupture of a Thin Film” Cryst. Growth Des.13, 5062–5067, 2013). You will extend these studies to othercrystals such as copper sulphate, potassium ferrocyanide and glycine, which have been shown to give qualitatively different patterns on both glass and mica surfaces, with curved rather than linear crystal arrays. The work involves optical and transmission electron microscopy, and suits careful and patient experimentalists.
Ispectroscopy
Professor Steve Evans
Project will write an ipad app to control the camera and flash on iphone to undertake simple spectroscopy that might form part of a home based diagnostics / home testing for monitoring patients health or early cancer detection.
Cell Deformation
Professor Steve Evans
Project will involve writing code to undertake image analyses of droplets or cells to distinguish between healthy and cancerous cell lines.
Cell capturing in a microfluidic device
Dr Jung-uk Shim
To be confirmed – contact supervisor for further information.
Multiplexed single molecule counting immunoassay
Dr Jung-uk Shim
To be confirmed –contact supervisor for further information.
Quantum Information
Topological Quantum Memories
Supervisors: Jiannis K. Pachos
Background: Physics should remain unchanged if we exchange two identical particles. This is a
fundamental symmetry with far reaching consequences. In three dimensions it dictates the
existence of bosons and fermions. In two dimensions a variety of statistical behaviours is
possible: arbitrary phase factors or even non-trivial unitary evolutions are allowed when two
particles are exchanged. Particles with such an exotic statistics are called anyons [1,2].
Anyonic systems can primarily serve as quantum memories. One can encode quantum
information in simple topological systems in such a way that it is shielded from the environment.
This is an important property, e.g. for constructing quantum hard disks. Fault-tolerance mainly
originates from two characteristics of topological systems. First, they have an energy gap that
protects the encoding state-space from environmental perturbations. Second, the encoding space
is highly entangled so that the information can be encoded in a non-local way. Hence, local
perturbations caused by the environment cannot access the stored information. The result is a
surprisingly effective and aesthetically appealing method for constructing a fault-tolerant
quantum memory.
The Project: While the resilience of topological systems against local Hamiltonian perturbations
has been recently demonstrated [3] the protection against thermal errors is still an open question.
The project is concerned with the toric code topological model (see Figure 1) and its faulttolerance
as a quantum memory.
Initially, we shall consider the effect Anderson localisation has on the coherent propagation of
errors that can destroy the encoded information in a time linear to the system size. Anderson
localisation aims to exponentially suppress the propagation of errors in the presence of disorder.
This can re-establish infinite coherence times for the memory [4]. This project is based primarily
on analytical work with the support of numerical studies.
The disordered toric code paradigm serves as a platform for testing the efficiency of topological
systems against temperature that contentiously generates errors. Including the environment in our
modelling the temperature-induced transport of anyons can be mapped to the coherent transport
of an extended system. As Anderson localisation can stop these errors from destroying the
information it is expected that it can protect the toric code from a finite temperature. Deriving the
fault-tolerance of the disordered toric code at finite temperature can be the holy grail of quantum technologies.
References:
[1] J.K. Pachos, “Introduction to Topological Quantum Computation”, Cambridge University
Press (2012).
[2] G. K. Brennen and J. K. Pachos, ``Why should anyone care about computing with anyons?",
Proceedings of the Royal Society A 464, 1-24 (2008), arXiv:0704.2241.
[3] S. Bravyi, M. Hastings and S. Michalakis, "Topological quantum order: stability under local
perturbations", arXiv:1001.0344.
[4] J. Wootton and J. K. Pachos, ``Bringing Order through Disorder: Localization of Errors in
Topological Quantum Memories’’, Phys. Rev. Lett.107, 030503 (2011) contributed talk at QIP
2011 in Singapore.
Hidden Quantum Markov Models
Dr Almut Beige
Hidden Markov Models (HMMs) are widely used in classical computer science to model stochastic processes with a wide range of applications. This project concerns the quantum analogues of these machines, so-called Hidden Quantum Markov Models (HQMMs). Using the properties of Quantum Physics, HQMMs are able to generate more complex random output sequences than their classical counterparts, even when using the same number of internal states. The purpose of this project is to quantify this statement by comparing the statistical properties of the output sequences of HMMs and HQMMs numerically and to become more familiar with both types of machines.
Entanglement spectroscopy of Quantum Matter
Dr Zlatko Papic & Dr Almut Beige
To be confirmed
Soft Matter
Saving the world one molecule at a time
3 experimental places – Dr Mike Ries
Summer Placement Research Project
Cellulose is the world’s most abundant naturally occurring organic polymer. Each year the amount of cellulose produced by Nature outweighs, by factors of thousands, all the combined man-made oil based polymers. It is an almost inexhaustible source of raw material for the ever-increasing need for biocompatible, biodegradable, environmentally friendly products and shows great promise for replacing conventional petroleum-based plastics.
Using polysaccharides, such as the cellulose molecule, brings valuable advantages: use of the largest “chemical reactor”, Nature itself; decrease of fossil oil dependence; reduction of CO2 emissions; development of the European forest and wood processing enterprises; efficient non-food use of agricultural products; production of biodegradable, allergy-free and recyclable materials. All this makes cellulose a truly sustainable material.
Ionic liquids (ILs) are salts that are in the liquid state at room temperature; they have melting points at or below ambient temperatures. Recently imidazolium-based ILs have been found to be direct solvents for cellulose and are therefore a very promising route for unlocking the full potential of cellulose.
This project is an excellent opportunity to work in an international multi-disciplinary collaborative group applying physics, imaging and soft matter physics to an industrially relevant problem. You will learn about Nuclear Magnetic Resonance (NMR), the underlying physics of MRI, and how a biopolymer can affect the solvent it is in and vice-versa. You will investigate the physics that links the microscopic world to the macroscopic one, using NMR to uncover the solution properties in terms of a molecular description of dynamics and structure.
Making Maxwell’s equations app-etising
Dr Mike Ries
In this project you will create an App to work on iOS devices that enhances the understanding of the second year undergraduate electromagnetism course. You will create a series of interactive tutorials that will cement the students’ understanding of Maxwell’s equations. This App will then be submitted to the Apple store where students can download it for free. If you ever wanted an App on the Apple store or make the second year course a little easier to follow, then here is your chance to make a difference!
Development of a microwave experiment for 1st year laboratory PHYS1060
Dr Peter Hine
The aim of this summer placement project is to explore the possibilities for developing the current microwave optics experiment. The first iteration of this experiment used a pair of large double slits to form a diffraction pattern in space which was measured using a E probe. Regrettably this proved too irregular to be used so last year we replaced this part of the experiment with the measured of the refractive index of a material. Unfortunately this second part is very similar to part 1, and so involves the students repeating almost the same measurements. The aim of this summer project is to revisit the double slits and see if there is some combination of slit width, separation and distance which give repeatable, and interesting results.
This proposed project is for the research and development of educational material.
Updating the Leeds 2D image analyser.
Dr Peter Hine
At Leeds we have a unique, and world renowned, facility for the measurement of the orientation of short glass fibres within an injection moulded part (e.g. an automotive clutch pedal). The current system was built in-house (by two previous PhD students) but it is becoming outdated in terms of the hardware/operating system. The routines are all written in Visual C so we would appreciate someone with knowledge of C, or programming in general, to give us some help in updating the system to newer hardware (already purchased) and software
Physics Teaching Enhancement and Education Research
To explore the relationship between students’ career aspirations and effective learning in Physics?