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School of Physics and Astronomy

Year 3 Project Catalogue

See the accompanying document "Year 3 Project Selection" for details about choosing projects and important deadlines.

If you need any advice about projects, contact the Project Coordinator, Dr David Westwood ([email protected]).

Academic Year 2017-2018

Year 3 Project Catalogue for 2017-2018

How do stellar clusters grow?

Supervisor: Dr P Clark

Project No.: 3701 Project Type: ASTRO

Project Description:

It is thought that over half of all stars form in stellar clusters — gravitationally bound swarms of stars in which violent dynamical interactions can occur. However, we still do not know how long it takes for these clusters to be assembled, or even how the properties of the gas and stars vary as the cluster grows in mass. This has caused many, heated arguments in the star formation community, mainly because the observational data is difficult to interpret. However, we can look to numerical simulations as a guide. The student will look at data from recent, state-of-the-art, computer simulation of cluster formation, to explore a) how rapidly the cluster is assembled, and b) how this would ‘look’ to an observer. We will then see if the discrepancies in the observed timescales for cluster assembly, and the properties of the clusters, are just due how the observational data is being interpreted. The student’s work will be roughly split (approx): 30% literature review; 40% data mining; 30% analysing data and writing up the report. This project is suited to students that like to dig into large data sets.

No. of Students: 1 or 2


Galaxy evolution with Herschel and the Hubble Space Telescope

Supervisor: Prof S A Eales



Our deep Herschel surveys allow us to see dust-enshrouded galaxies back to very early times. However, the poor resolution of Herschel means that the galaxies just look like blobs on the images. Fortunately, the Hubble Space Telescope has been carrying out public surveys of many of the deep Herschel fields (the Cosmic Assembly Deep Extragalactic Legacy Survey). The students will use a combination of the Herschel and Hubble data to investigate the evolution of galaxies, in particular how disk galaxies evolve into elliptical galaxies. The project will require the student to use a number of standard astronomy analysis packages and do some programming.

No. of Students: 1 to 4


M87 and its jet

Supervisor: Prof W Gear



M87 is the dominant galaxy in the centre of the nearby Virgo cluster. It also has one of the first-discovered and most prominent "jets" emerging form its centre. A student on this project will review the properties of M87 and of jets and then use recently obtained data far-infrared and submillimetre from Herschel and JCMT to try to isolate the emission from the jet from that of the remainder of the galaxy and determine its spectrum and origin of the emission.



Origins of the Solar System

Supervisor: Dr J S Greaves



The Sun's planets were born out of a disc of orbiting rocky particles and gas. Using blackbody emission at radio wavelengths, we can image zones containing 'pebble' sized particles in similar discs around very young stars. In this project, the student will work with radio data from the Very Large Array (VLA), and analyse images at 1 cm wavelength of circumstellar discs in the Taurus and Ophiuchus star-forming regions. From measurements of the radio flux, radial profiles of surface density will be constructed. By comparing these to models of the Minimum Mass Solar Nebula, the student will assess whether conditions under which the Sun's planets formed are common, rare, or anomalous.



Star formation studies with the Herschel Space Observatory

Supervisor: Dr P Hargrave



The project aims to use the large amount of publicly available Herschel far-infrared data to study regions of star formation in our Galaxy.

Objectives:i) To learn about Herschel and its dataii) To extract data from the Herschel data archiveiii) To reduce and analyse those dataiv) To compare the data with current theoretical predictionsv) To place the data in context with previous observationsvi) To confirm or disprove theoretical ideas of star formationThe student(s) will spend their time working with state-of-the-art data from a telescope that is still orbiting, and the work may lead to the student(s) being involved in a research publication.



Identification of strong gravitationally lensed galaxies

Supervisor: Dr M Negrello and Prof S Eales



Gravitational lensing is a powerful astrophysical and cosmological tool that can be used to detect very faint galaxies in the distant Universe, to study their morphological properties downs to scale difficult (if not impossible) to probe with the largest telescopes at present and to constrain cosmological parameters. Gravitational lensing occurs when the light from a distant galaxy is deflected by a foreground mass – commonly a massive elliptical galaxy or a galaxy group/cluster. Since this phenomenon relies on a chance alignment between the background galaxy, the foreground lens and the observer, it is quite rare. Therefore the discovery of lensing systems involves the sifting of large data sets. The student will investigate the different methods developed over the last years to discover gravitationally lensed galaxies in optical/sub-millimeter/millimeter/radio surveys and will compare them to understand the (dis)advantages of one method over the others. Depending on performance, the student will have a chance to search for lensed galaxies in the wide-area extragalactic surveys conducted with the Herschel space observatory at sub-millimeter wavelengths.



Do converging networks of interstellar filaments point towards massive star-

forming cores?

Supervisor: Dr N Peretto



Recent Herschel observations reveal that filaments represent a key intermediate stage in the accumulation of matter from diffuse interstellar clouds to star progenitors (i.e., cores). In nearby and low-mass star-forming regions, cores are usually embedded in the densest filaments, forming, we believe, as the result of gravitational instabilities running along them. In some cases, cores are found at the converging point of networks of filaments, also called hubs. In fact, the most massive core ever observed in the Galaxy has been observed at the centre of a collapsing hub, filaments feeding the central core in cold and pristine gas. Therefore, one can wonder is the presence of a hub is an indirect indication of the collapse of the parent cloud, gravity pulling filaments towards the centre of the potential well. If, as suggested in some theories of massive star formation, cloud global collapse is a necessary step towards the formation of a massive star, then hub-filament systems could indicate the exact location of massive star in formation.

In this project, the student will use 8micron extinction images of the Galactic plane to systematically identify interstellar filaments towards dense star-forming clouds. A filament algorithm and method to quantitatively measure filament convergence will have to be developed. Then, the student will correlate such a "hub map" with sub-millimetre dust continuum observations to check if high convergence correlates with high mass concentration. The student will also test this method on ALMA surveys of some of the most massive cores in the Galaxy.



Molecules in dark clouds

Supervisor: Dr S Ragan



Stars form in giant clouds of (predominantly) molecular hydrogen (H2), but at the low characteristic temperatures in these clouds, we can not observe H2 directly. The next most abundant molecule in these clouds that we can observe is carbon monoxide (CO). Using maps of two different "types" (called isotopologues) of CO which emit differently depending on the density and temperature, it is possible to study how the physical conditions in molecular clouds change with their environment. In this project, the student(s) will learn to analyse spectral line data taken at the IRAM 30-meter telescope, by fitting simple models to the emission profile in order to infer physical properties. They will also need to undertake a literature study to relate the findings from the CO analysis to what is already known about the clouds we are studying.

The work involved will be roughly split between literature review (20%), analysing spectral line data (50%) and writing up the results (30%). This project involves doing Python programming.



Observational astronomy with the Faulkes Telescope Project

Supervisor: Dr P Roche and Dr F Lewis



A range of observational projects are possible using the 2m, 1m and 0.4m LCO robotic telescope network, covering the following topics:

Massive stars and open clusterse.g. identification of emission-line stars from colour-magnitude and colour-colour diagrams; production of lightcurves for variable stars

Variable starse.g. studying the variability of a variety of different types of variable stars or X-ray binary (neutron star and black hole) systems, looking for correlations , periodicities, outbursts etc.

Exoplanet occultationse.g. observing transits of known exoplanets and deriving system parameters from analysis of the lightcurves

Students will initially carry out analysis of archival data (taken since 2004), then will schedule and obtain new observations using the LCO network. These data will be analysed and (depending on the actual topic chosen) information on the astronomical objects extracted. Observations will mainly consist of optical photometry, but in some cases spectroscopic observations may also be possible.



Lithopanspermia

Supervisor: Dr A Cartwright

Project No.: 3709 Project Type: ASTRO or PHYS


You will perform n-body simulations to investigate the probability of life being transported within the solar system, particularly between Earth, Mars, Venus and the potentially habitable moons of Jupiter.Good programming skills required.



How fast do molecular clouds grow?




Stars form in large clouds of molecular gas, often referred to as Giant Molecular Clouds (GMCs). Observations show that these clouds come in a bewildering variety of shapes and sizes and masses, however there is much that we still do not understand. For example, we have very little idea as to how quickly these clouds can form and grow in mass, and whether this plays an important role in their ability to form stars. In this project, the student will examine several models for how clouds can accrete gas from the interstellar medium. This will involve designing a short computer program - in IDL/Fortran/C(++)/Python - to model the growth of ensembles of clouds. During the project the student will learn how to model complex, time-varying systems. This will also be a good introduction to physical processes that control the dynamics of the gas in the interstellar medium. The student’s work will be roughly split (approx): 20% literature review; 40% designing code; 20% running simulations; 20% analysing data and writing up the report. This project is best suited to students that enjoy writing computer codes.



N-body modelling of young protostellar systems




Observations suggest that stars are born in small groups of around 2-4, which gravitationally interact with one another while the stars grow in mass. We will model this phase of the young stars life, by performing N-body simulations of small groups of stars, to see how quickly they can be ejected from their natal ‘protostellar core’ — the dense core of gas in which they formed. We will also model how these stars accrete mass during these interactions. The student will write their own N-Body simulation code, and also the scripts to look at the properties of the stars as the N-body system evolves. The student’s work will be roughly split (approx): 20% literature review; 30% designing code; 20% running simulations; 30% analysing data and writing up the report. This project is best suited to students that enjoy writing computer codes.



Cold gas and dust in the ALMA Fornax Cluster Survey (AlFoCS)

Supervisor: Dr T A Davis



Much of our current understanding of the way galaxies form and evolve is based on observations of galaxies in cluster environments. Cluster galaxies differ significantly from their field counterparts, and these differences can provide crucial clues as to the primary external influences on galaxy evolution. Nearby clusters have played a key role in shaping our understanding, as they can be studied in a level of detail that is not possible for more distant systems. In this project, students will use data from the ALMA Fornax Cluster Survey (AlFoCS; PI T. Davis) and HeFoCS (the Herschel Fornax Cluster Survey; PI J. Davies) to study the evolution of gas and dust in galaxies that lie within the Fornax Cluster. A variety of issues can be addressed, including the relative extent of the gas component, the relationship between gas and dust in the cluster, and the dynamics of the gas. This project requires primarily observational/analysis skills, and will involve students working with ALMA data in standard software tools, and undertaking some simple programming.



Shocked molecular hydrogen and star-formation in IC1024




Early-type galaxies (ETGs) have been traditionally seen as `red-and-dead', with little or no cold gas, and no ongoing star-formation. Evidence has mounted in recent years however some of these objects do have cold gas reservoirs. Interestingly this gas may be less efficiently converted into stars than that found in spiral and starburst objects. Whether this is caused by the deep potential well, harsher irradiation from old stellar populations, or greater prevalence of shocks and AGN has yet to be determined. Students taking on this project would attempt to learn more, using data from the Very Large Telescope of ETG IC1024. Using H2 excitation diagrams and theoretical models of photon dominated regions the students will derive the physical conditions within the hot molecular ISM of these galaxies, and determine if it has been directly affected by harsh irradiation, hot gas, or shocks. The conditions within this material will shed light on the importance of these mechanisms in the suppression of star-formation in ETGs. This project will require the student(s) to use standard software, and write simple scripts to analyze and plot astronomical data.



Where does the gas and dust in early-type galaxies come from?




The most massive galaxies in our universe (so called “early-type galaxies”) have relatively uniform optical properties, red colours, and low rates of ongoing star-formation. Because of these, they have often been thought to be gas and dust free. This is not the case, however, as recent work has shown up to half of early-types have some form of cold-interstellar medium and/or dust. The origin of this material remains uncertain: does it cool from stellar mass loss, or is it accreted in mergers with smaller galaxies? The aim of this project is to use data from the Gemini telescopes and/or the Sloan Digital Sky Survey to estimate the gas metallicity in early-type galaxies that have a cold interstellar medium. Comparing this metallicity to that of the stars can help us distinguish the origin of the gas in these enigmatic objects. This project will require the student(s) to use a number of standard astronomy analysis packages to reduce optical spectra, and fit emission lines. The students will also be required to do some basic programming.



Designing large arrays of Kinetic Inductance Detectors

Supervisor: Dr S Doyle



Kinetic Inductance Detectors (KIDs) are rapidly becoming the technology of choice for mm – sub-mm instrumentations (90GHZ – 1.0 THZ). KIDs are naturally broadband detectors that can be multiplexed into large format arrays with exquisite sensitivity. Multiplexing KIDS into large arrays requires a number of design considerations to i) ensure that all detectors can be read out within a certain bandwidth of readout electronics, ii) cross-talk between pixels is minimised, iii) focal plane area is used as efficiently as possible and iv) the array performance is maximized for a certain set of observing conditions. This project will involve studying the design aspects of making large arrays of KIDs to develop design rules and models for their performance. Models will be tested against real data acquired from existing large KID arrays. Specifically the student will:

Learn the basic principles of superconductivity relevant to KIDs.Learn the concepts of microwave theory related to the readout of KIDs.Use a combination superconductivity theory and python code to assess the performance of KID arrays at sub-Kelvin temperatures under typical observing conditions.This project has the potential for some experimental testing to acquire data from existing designs but due to the complexity of the equipment used, this work involves working alongside and assisting research staff.



Optimizing Kinetic Inductance Detector towards improved optical efficiency




Kinetic Inductance Detectors (KIDs) are rapidly becoming the technology of choice for mm - sub-mm instrumentations (90GHZ - 1.0 THZ). KIDs are naturally broadband detectors that can be multiplexed into large format arrays with exquisite sensitivity. The Cardiff invented Lumped Element Kinetic Inductance Detector (LEKID) has already been demonstrated across a range of application. The absorption of light by a LEKID requires careful design of the overall pixel architecture. In this project the student will study the design and of a LEKID device optimized for absorption over a given optical bandwidth tailored to either an industrial of astronomical application. The student will be required to:

Learn the principles of transmission line theory used to model optical absorption of KIDs.Use a combination of python code and commercial software to model and optimize LEKID optical performance.Use python code to analyze experimental data to characterize the optical absorption properties of a real device.This project has the potential for some experimental testing of designs but due to the complexity of the equipment used, this work involve working alongside and assisting research staff.



The origin and evolution of stardust in nearby galaxies

Supervisor: Prof H L Gomez



The Herschel ATLAS project is the largest Open Time survey carried out with the Herschel Space Observatory. Herschel is the largest, most powerful infrared telescope and is the first space observatory to observe from the far-infrared to the submillimetre waveband, unveiling the hidden dusty Universe to us for the first time. Our work with the Herschel ATLAS data (Dunne, Gomez et al. 2011; Rowlands, Gomez et al. 2014) has shown that the dust content of the Universe has changed much more rapidly than we expected in the last few billion years and this is a big mystery.

In this project, you will build on an existing model written in python and publicly available on github. The existing model is able to describe a galaxy fairly well, predicting the build up of dust and metals as gas is consumed into star formation. It matches some observational properties of galaxies in the early universe and spiral galaxies closer to us. However, it currently includes a very simple way to account for the fact that outflows and inflows of gas occur in galaxies.

To realistically compare this model with observations of galaxies requires a review of more sophisticated (and tried-and-tested) approaches to include gas inflows and outflows. Ultimately, you will compare the model with either nearby samples of dusty galaxies, or hundreds of thousands of galaxies in the Herschel ATLAS fields from the last 5 billon years.

This is mostly a theoretical project and will suit anyone with a physics or astrophysics background who enjoys working with analytic (back-of-the-envelope) calculations and/or those with some confidence in python (or other programming language). Physics students who like to apply their theoretical know-how to the Universe are particularly welcomed to apply.



Orbits of planetary debris

Supervisor: Dr J Greaves



Collisions between comets orbiting stars produce belts of rocky debris. These particles emit blackbody radiation that can be studied with infrared and millimere telescopes. In the survey 'SCUBA-2 Observations of Nearby Stars', we have found a number of puzzling systems where the cometary debris appears much brighter to one side of the star than the other. The competing explanations are that a dwarf planet has broken up in the belt, or that an unseen massive planet has forced the comet orbits in one direction (like the hypothetical Planet X in the solar system). The aim of this project is to write a code to track the orbits of test particles (e.g. wih the velocity Vernet algorithm) , and see if their distribution resembles the observed data. This project would suit students who enjoy coding and the opportunity to test a model against real and unexplained astronomical data. A basic understanding of the physics of orbits will be needed; some background in examining astronomical images would be useful but is not essential.



Spinning nano-diamonds in space

Supervisor: Dr J Greaves



Radio emission peaking at around 30 GHz in frequency occurs from gas clouds around stars, between stars, and in other galaxies. This 'anomalous microwave emission' is thought to come from rapidly spinning nano-particles that act as electric dipoles. We have recently identified nano-diamonds as a possible carrier particle. The aim of the project is to write a code to see how the shape of the radio spectrum changes with the type of diamond and its shape, size and electric charge. This project would suit students who enjoy coding and testing model results against data. The physics of the radiation is described in standard papers, and a basic understanding of astronomical methods would be an advantage but is not essential.



The far infrared emission of asteroids

Supervisor: Prof M J Griffin



The thermal emission from an asteroid depends on its temperature distribution and on the nature of its surface as well as its distance to the Sun and how it is seen from the Earth. Measurements of the thermal emission of asteroids can be used to infer important properties including size, temperature and surface characteristics. Because asteroids are moderately bright point-like sources, they are also useful as standard calibration sources at far infrared and submillimetre wavelengths (50 emission is well understood.

Two models of asteroid emission are commonly used – the so-called Standard Thermal Model (STM) and a more elaborate thermo-physical model. The project will involve (i) reviewing and understanding the asteroid models based on the published literature; (ii) coding the STM to produce a predicted spectral energy distribution (SED) for a given asteroid and a given observation date; (iii) comparing the predicted SEDs with published results of the thermo-physical model; (iv) comparing the results of both models with observational results on selected asteroids from the Herschel Space Observatory.



Bringing astronomy to a wider audience

Supervisor: Dr C North and Ms W Sadler



How can we engage non-specialist audiences in the contemporary physics and astronomy research happening at Cardiff University? Whether they are using the Herschel Space Observatory, simulating the formation of stars, or detecting gravitational waves, astronomers should consider how they communicate their work to school students, teachers and the general public - but it isn’t always easy. Some of you may have been inspired to study science by a particularly inspirational teacher or even a science presenter on TV. Some of you may be thinking of becoming that inspiration to the next generation, and training to become a school teacher or science communicator. In this project you have the opportunity to get a taste of what school teaching and communication of science is about. In conjunction with your supervisor you will choose an area of Cardiff astronomy research and develop resources to help teachers, students or the general public understand and engage with it. You will have to consider how the topic links into the school curriculum or how you can use cultural hooks or events to connect the research with a wider audience if speaking to an adult audience without astronomy knowledge. Over the course of a year you will develop a pack of material to support the teaching or communicating of the topic. The pack may include lesson plans, suggested experiments and demonstrations, additional background reading material for students and teachers, homework/activity sheets as well as appropriate clips and images. You will then be expected to test out the material at a local school or a public event to evaluate the success of your material.

As part of your project, you will obtain a background into the different school exam curricula (and what is required of both teachers and students), will learn about different teaching and learning styles, and will develop your skills of explaining physical and astronomical concepts using real-life analogies and simplified mathematical explanations. This project is well-suited to either astronomy or physics students who have an interest in going into teaching or science communication and who would like to find out more about what is really involved. Each student will work on individual projects, with a weekly group seminar discussion on aspects of the projects that are common to all.

Would suit a minimum of 2 to maximum of 4 students



Performance Characterization for the ARIEL space telescope

Supervisor: Dr A Papageorgiou



ARIEL is a European Space Agency candidate mission, planed for launch in 2025. During its four-year mission ARIEL will observe hundreds of exoplanets (500-1000) in the visible and the infrared with its meter-class telescope. The analysis of ARIEL spectra and photometric data will allow to extract the chemical fingerprints of gases and condensates in the planets’ atmospheres, including the elemental composition for the most favorable targets.

In the current phase of the mission, all of the missions aspects need to be modelled and characterised; one of these aspects is the likelihood of background stars, bright in ARIEL's observing wavelength, to be within ARIEL's field of view.

For this project, the student will have to write software to access information from public star catalogues, select stars that are within close proximity to the ARIEL target list, estimate the brightness of these stars in ARIEL's observing band and finally quantify the likelihood that a background star will be interfering with the observation of a target.

This project has a heavy emphasis on Programming (Python), Data Analysis/Reduction and Model Fitting (fit black body to catalogue star magnitudes in order to estimate their brightness in ARIEL's waveband)



Characterising the size and mass distribution of molecular clouds in the Whirlpool

galaxy using Hubble extinction maps

Supervisor: Dr N Peretto and Dr Ana Duarte Cabral



Stars form in large clouds of cold interstellar dust and gas. The physical properties of these structures will determine the star formation rate, i.e. the rate at which gas mass is converted into stellar mass. Star formation rate is arguably the single most important quantity in galaxy evolution, dictating the pace at which galaxies evolve across cosmic times. As a consequence, understanding what are the physical properties of molecular clouds, these stellar nurseries, is of prime importance. In 2010, a very peculiar cloud has been discovered in our own Galaxy, called since then Nessie. What is remarkable with Nessie is that it is 100pc long, but only 1pc wide, and has a nearly uniform velocity. In a very turbulent interstellar medium such as in the Milky Way, the formation of such velocity coherent structure is really unclear. Since the discovery of Nessie, a number of other studies have looked for similar Milky Way clouds, and a number of potential candidates have been identified. However, the problem with Galactic observations is confusion: because we are in the Milky Way, a large number of unrelated structures are overlapping on every line-of-sight which makes difficult the identification of individual structures. In that respect, identifying individual clouds in external galaxies is easier.

In this project, the student will use Hubble data of the iconic Whirlpool Galaxy (M51). The goal of the project will be to identify the population of molecular clouds that are seen in extinction in Hubble images at very high angular resolution. By characterising the distribution of lengths, widths, and masses as a function of their location in the galaxy (spiral arms, inter-arms, distance to the centre) the student will be able to identify in which environment Nessie-like clouds can form, and eventually come up with a physical scenario that can explain how 100 pc long velocity coherent structures can survive in the turbulent interstellar medium. If time allows, the student will also look into star formation tracers in order to search for potential correlations between cloud morphology and star formation rates.



From darkness to light: when star formation lights up infrared dark clouds

Supervisor: Dr N Peretto



Stars form in dense, cold, molecular clouds. Very early during their evolution, and as a result of absorption by interstellar dust grains, these clouds can be seen in silhouette against the background light of the Milky Way. As star formation goes on, the radiative and mechanical feedback from the new born stars impact the physical properties of the host clouds, and start to illuminate them from the inside. Dark clouds are not dark anymore. Statistics about the "darkness" level of star-forming clouds as a function of their mass and size can potentially tell us a lot about how clouds evolve in time, and how important stellar feedback is in regulating star formation. This area of star formation is observationally poorly constrained, and is at the centre of numerous debates within the star formation community.This project aims at identifying star-forming clouds in the Milky Way using the Herschel far-infrared images of the galactic plane, and at characterizing their infrared darkness using the mid-infrared data from the Spitzer telescope. The distribution of infrared darkness as a function of cloud masses, sizes, densities will be then performed and compared to what we expect from different star formation models. This project could bring a new element to the debates on cloud evolution and the role of stellar feedback.



Hunting for accretion discs around massive star progenitors

Supervisor: Dr N Peretto and Dr C North



Despite their importance in regulating the energy budget of galaxies and enriching the interstellar medium with heavy elements, the formation of massive stars remains one of the mysteries of the Universe. One very much debated aspect of the massive star formation concerns the accretion process, from the cold, dusty, gaseous envelope surrounding the massive protostar to the protostar itself. It is believed that this process involves the presence of a disc, which allows the continuous accretion of material while also permitting the huge radiation pressure from the massive protostar to escape. At present, only a handful of discs surrounding massive protostars have been discovered, limiting our ability to build up a coherent scenario of the accretion process onto massive protostars. By gazing at mid- to far-infrared images from the WISE and Herschel missions, we recently discovered a new disc candidate - largely by accident! We are now in the process of observing this source with ground-based telescopes to confirm its nature. These datasets are huge, and may be hiding many other new discs. The goal of this project is to search for these sources by combining WISE and Herschel data. The morphological appearance of these disc candidates is complex, meaning that identifying them in an automated way is not easy. You will therefore first evaluate the feasibility of an automated search by performing some test identifications, and use the outcome of this preliminary study to inform an eventual citizen science project as part of the Zooniverse.This project will lead to the identification of hundreds of disc candidates around massive progenitors, and could be transformational for our understanding of the formation of massive stars.



Infrared dark clouds and holes in space

Supervisor: Dr N Peretto and Dr C North



Infrared astronomy allows us to see clouds of interstellar dust – the material from which stars are made. Even back in the 1980s mid-infrared observations showed patches of sky that were dark in the infrared, and these were assumed to be regions where a much colder cloud of dust, opaque and dark at those wavelengths, was blocking the light from background regions. These cold, silhouetted clouds were dubbed Infrared Dark Clouds (IRDCs), and there are now catalogues of tens of thousands of them.

It would be expected that longer wavelength observations would show the colder material, but some regions remained dark – indicating that there are actually holes in the interstellar medium (ISM). These holes, often blown by the strong stellar winds from young stars, can have knock-on effects on the surrounding regions and the associated star formation. Studying the IRDCs and the holes in space requires analysis of lots of data, including from the Spitzer Space Telescope and the Herschel Space Observatory.

Identifying which IRDC are in fact dark clouds and which are holes in the interstellar medium is rather difficult, and in 2012 we ran a citizen science project as part of the Zooniverse's “Milky Way Project”. Citizen scientists were asked to compare mid- and far-infrared observations (from Spitzer and and Herschel) to identify which objects were holes and which were clouds, producing a catalogue of over 10,000 objects with “citizen science” scores.

Your project will involve using data from Spitzer and Herschel to study a selection of IRDCs and holes in the ISM, deriving the temperature and density of the material based on a range of physical assumptions. You will also analyse the database of citizen science results to extend that analysis to the full dataset of over ten thousand objects. The work would involve writing code to manipulate the data and analyse the results.

This project would be well suited to an astronomy student who has an interest in data analysis, or a desire to be involved in citizen science.



Frequency Selective Surfaces (FSSs) and general metamaterials development for

mm-wave applications

Supervisor: Dr G Pisano, Prof P A R Ade and Prof C Tucker



The Astronomy Instrumentation Group has been fabricating metamaterial devices for use in submillimeter wave instrumentation for many years. Whilst most of the components have been used to perform selective optical filtering other applications of this technology are currently being explored such as the ability to make flat lenses, wideband dispersive devices, HWP and even negative index materials. These research avenues could lead to improved optical efficiencies and/or new instrument concepts.

Examples devices are:

-Mesh filters and dichroics: used to define the operational frequency bands of an experiment. -Mesh Half Wave Plates: made with anisotropic grids, used to modulate the polarisation of the radiation.-Mesh Polarisers: used to convert linear into circular polarisations.-Near-zero-permittivity materials: new exotic media where the radiation phase is almost 'frozen'; these materials allow tailoring the radiation pattern of an arbitrary source.

The goal of this project is to: - model the electromagnetic radiation in presence of FSSs/metamaterials; - design an FSS/metamaterial device using finite-element analysis software (HFSS: High Frequency Structure Simulator) for operation at millimetre wavelengths. - follow the device manufacture within the department facilities; - experimentally characterise the device using a Fourier Transform Spectrometer (FTS) or mm-wave Vector Network Analyzer (VNA) available within the Astronomy Instrumentation Group.



Astronomy in the classroom

Supervisor: Dr P Roche



In this project you have the opportunity to get a taste of what school teaching is about, whilst working alongside a team of astronomy educators. Some current activities include the Faulkes Telescope Project (robotic optical telescopes), Gaia, SOHO (ESA space missions), Down2Earth (asteroids, comets and impacts), QuarkNet Cymru (cosmic ray astrophysics) and astronomy materials for public events and music festivals.

You will choose a physics concept from the GCSE or AS/A2 level syllabus, and over the course of the year will develop materials to cover the teaching of the topic. This could include producing lesson plans, experiments and demonstrations, additional background reading material for both students and teachers, homework/activity sheets as well as appropriate clips and images.

As part of your project, you will study some educational theory, and look at the different school exam syllabi (and what is required of both teachers and students), learn about different teaching and learning styles, and develop your skills of explaining physical concepts using real-life analogies and back-of-the-envelope estimations.

This project is well-suited to astronomy students who have an interest in going into teaching or science communication, and who would like to find out more about what is really involved.

Each student will work on individual projects, with a weekly group seminar discussion on aspects of the projects that are common to all.



Does becoming a physics presenter affect your attitude to physics as a subject?

Supervisor: Ms W Sadler




Many school students at secondary school level have already disengaged with physics and feel it is not for ‘people like them’. The UK needs a larger number of students to choose physics at a higher level, partly because it has a positive effect on the economy of a country, but also because physics graduates are in short supply for related jobs in policy, business and teaching. But how can we engage with the disengaged students?

Science made simple (SMS) is a spinout company from the School of Physics and Astronomy with the mission of engaging more people with science, and especially the physical sciences. As part of this work they have begun training school students to become physics ‘buskers’ themselves; learning presenting and theatrical skills alongside the science required to entertain an audience. This training is often done with students who have a very low self-proclaimed interest in physics. What happens to these students as they become science presenters? Does their attitude to science and physics change?

This project will involve working with SMS staff and the possibility of involvement in a European study (involving Spain and France) to examine whether learning science through performance is an effective way to change the attitudes of disengaged students.

As part of your project, you will obtain a basic background in social science research methods and educational issues. This project is well suited to either astronomy or physics students who have an interest in going into teaching, policy or science communication.

No. of Students: 1


What physics do audiences learn from outreach activities?




Project Description: Science made simple is an award-winning outreach company that has a mission to inspire the next generation of scientists and engineers. As a spin-out company and partner with the School of Physics and Astronomy they have a range of physics-related presentations that aim to communicate various aspects of physics and astronomy to school and public audiences and reach over 60,000 people each year. But how successful are they at achieving that aim?

Using existing literature on areas such as ‘how audiences learn’ and ‘why performance can be an effective tool for engagement’, you will develop your own evaluation tool to assess the success of one, or multiple physics presentations.

By working in partnership with the staff of ‘science made simple’ and collecting data from the audiences they work with – you will have a real-life opportunity to provide research data that can have applications to how the company develop future products.

As part of your project, you will obtain a basic background in social science research methods and educational issues. This project is well suited to either astronomy or physics students who have an interest in going into teaching, policy or science communication.



Why do physics students choose physics?




Project Description: Hundreds of thousands of pounds are spent each year on initiatives that aim to get more students studying physics at University. The UK has a shortage of physics graduates and it has been shown reliably that countries with higher levels of STEM graduates do better economically.

But how much do we know about what motivates people to study physics at university? Using quantitative and qualitative data from surveys and interviews with undergraduate students, this project gives the opportunity to collect data that could inform practitioners in the promotion of physics to school students and the general public.

Was it Brian Cox? Was your mother or father a physicist? Did you get a telescope for your 7th birthday and just fell in love with astronomy? Also, are men and women motivated differently? How about those who choose Engineering instead of Physics?

Using existing literature and by collecting your own data, this project will help answer the question of what motivates physics students.

As part of your project, you will obtain a background in social science research methods and educational issues. This project is well suited to either astronomy or physics students who have an interest in going into teaching, policy or science communication.

No. of Students: 1


Searching for gravitational waves with LIGO

Supervisor: Prof P J Sutton



Gravitational waves are oscillations in the curvature of spacetime produced by violent events such as black-hole collisions and the core collapse of massive stars. The first observed gravitational-wave signals, due to the mergers of black hole binaries, were reported by the LIGO Scientific Collaboration in 2016.

This project will use the X-Pipeline software package developed at Cardiff to analyse data from the first two observing runs of Advanced LIGO (in 2015-16 and 2016-17). The search will target transient gravitational-wave signals associated with astrophysical events such as fast radio bursts, x-ray flashes, high-energy neutrinos, or nearby supernovae. The student will select one of these types of events, conduct a brief review of the literature on source models for these events and their associated gravitational-wave emission, and then analyse the LIGO data with X-Pipeline to look for associated signals. Familiarity with python and matlab is helpful but not essential.

Recommended reading:

P J Sutton et al., "X-Pipeline: an analysis package for autonomous gravitational-wave burst searches" http://iopscience.iop.org/article/10.1088/1367-2630/12/5/053034/meta

B P Abbott et al., "Search for Gravitational Waves Associated with Gamma-Ray Bursts During the First Advanced LIGO Observing Run and Implications for the Origin of GRB 150906B" http://inspirehep.net/record/1499860



How do we learning (physics)? Enabling teaching and learning to work together

Supervisor: Dr D I Westwood



The aim of this project is to identify teaching approaches that will aid students as they struggle to learn physics (in School and /or University).Objectives of the project include: investigation of the field through a literature survey; a reflective consideration of personal learning strategies; a study (in a School and/or University) of teaching processes in practice and how their structure supports or hinders learning. The expected final outcomes of the project are well developed teaching strategies likely to benefit student learning.

Context: We are beginning to understand what is important when our brains are rewired by the (effortful) processes of learning. For example (and disappointingly) if a learning process is easy it is unlikely to be effective. In addressing this the literature refers to terms such as "consolidation" and "calibration" and approaches such as "retrieval practice", "spaced retrieval" and "testing". In this School continual assessment can be seen to act in support of consolidation and calibration, but retrieval practice is largely left for students to individually sort out for themselves in preparation for exams. All in all there appears to be scope for significant gains through a better coordinated or informed approach.

Students interested in this project may be considering a career in education.



Evaluation of Monte Carlo methods for simulating diffusion magnetic resonance

imaging

Supervisor: Dr L Beltrachini

Project No.: 3733 Project Type: MED PHYS


Diffusion Magnetic Resonance Imaging (dMRI) is an imaging technique that allows to characterise brain structures in the mesoscale in vivo and non-invasively. This is done by studying the diffusivity of water molecules within the tissue, which is mostly defined by the surrounding structures. To understand this phenomena in real-scenario situations, it is necessary to perform numerical simulations, for which Monte Carlo methods are generally used. These methods consist of representing each water molecule individually, as well as their random movement and interaction with the surrounding environment (also referred to as Brownian motion).

In this project, the candidate will review different algorithms for performing such computational experiments. The advantages and limitations of each of them will be evaluated. Special attention will be paid to efficient algorithms aimed to reduce the computational burden to a minimum. These methods will be tested in realistic scenarios representing brain tissue in the mesoscale (i.e. at a cellular level). This project is particularly suited to students with an interest in computational physics and its application in neuroimaging. The candidate should be familiar with Numerical Analysis (i.e. attending to PX3143) and programming.



Vessel filtering and segmentation from high resolution magnetic resonance images




Analysis of the human cerebral vasculature is important for the diagnosis of different diseases and syndromes, such as stroke or vascular dementia. To determine pathological changes in the vascular network, the vessel trees need to be segmented and quantified. Magnetic resonance imaging (MRI) is a widely-utilised technique for performing such task. Standard MRI-based methods were shown to capture major cerebral vessels reliably. However, they often fail to detect small vessels, whose contrast is suppressed due to the limited resolution of standard (1.5-3T) MR scanners. This problem can be solved using high field (7T) MR scanners, which deliver higher resolution images in the same amount of scanning time.

In this project, the candidate will implement standard vessel filters for segmenting the vascular network. This will be applied to high-field MR images acquired in CUBRIC. Different algorithms will be reviewed, implemented, and compared. This project is particularly suited to students with an interest in data analysis and image processing. The candidate should be familiar with Numerical Analysis (i.e. attending to PX3143) and programming.



Evaluation of the effect of overlying tissue on ultrasound image quality

Supervisor: Dr K Bryant



The aim of this project is to design a method to investigate the effect of overlying tissue on ultrasound image quality. You would be expected to research, design and produce a suitable measurement method. You would then use this method to investigate the effect of overlying tissue on image quality and measurement accuracy using ultrasound phantoms and student volunteers.

No. of Students: 1or 2


Do graduated compression stockings work?

Supervisor: Dr R Morris



The aim of this project is to investigate how graduated compression stockings (GCS) affect the body. Graduated compression stockings are widely used in UK hospitals to prevent deep vein thrombosis (DVT), and are recommended by NICE. Their manufacturers claim that they increase blood flow velocity which prevents clots forming the in the veins. However, the evidence to support this claim is old, and newer research had not replicated the effect. In this project you would investigate how GCS apply pressure to limbs, and how different pressures affect blood flow, and vein dimensions. You would examine the effects of the position of a patient on veins and determine the conditions under which blood would pool in the limbs. You would be expected to learn to use a Doppler ultrasound scanner to measure blood flow velocities and measure the size of the veins of the legs. The work could be validated in a range of healthy volunteers, and could be extended to assess in impact of different environmental conditions and body shapes, and ultimately produce a recommendation for hospital use of GCS.

The project is for a PAIR of students (since it will require cooperative experimental work).

No. of Students: 1PAIR


Optimising Intermittent Pneumatic Compression for Deep Vein Thrombosis

prevention.

Supervisor: Dr R Morris



The aim of this project is to investigate how intermittent pneumatic compression (IPC) for the prevention of deep vein thrombosis (DVT) can be improved. Intermittent pneumatic compression is used extensively in hospitals worldwide to prevent DVT in high-risk patients. Rhythmic compression of the limbs stops blood becoming static in deep veins and prevents clotting. However, the pressure the cuffs apply, and the timings of the compression, is based on convention rather than sound scientific investigation. In this project you would investigate how IPC affects blood flow, and how changing the timings and pressure affects the amount of blood moved from the limbs. You would need to determine whether this depends on individual physiology, environments conditions and limb position. You would be expected to learn to use a Doppler ultrasound scanner to measure blood flow velocities. The work would need to use several healthy volunteers, and could be extended to look at a range of different cuff designs and to look at the effects on arteries and limb dimensions. Your objective would be to recommend the optimal cycle for IPC systems.

The project is for a PAIR of students (since it will require cooperative experimental work).

No. of Students: 1 PAIR


Reliably measuring functional connections in the brain

Supervisor: Dr K Murphy



Functional magnetic resonance imaging (fMRI) uses the magnetic properties of blood to measure neural activity in the brain. When neurons are active, they consume oxygen causing blood vessels in the region to dilate to bring more blood. This is the basis of the fMRI signal. Recently, researchers have been using these signals to examine the brain "at rest". Brain regions whose signals fluctuate in the same way over time are said to be functionally connected, that is, they form part of a neural network in the brain that performs a specific task. However, because the fMRI signals are not a direct measure of neural activity, they are susceptible to many confounds that affect the blood signal: motion, cardiac, respiration, blood pressure, etc. These in turn affect the measure of connectivity - how strongly the regions are thought to be connected.

In this project, the student will examine recently collected data. The effects of various preprocessing steps designed to limit noise will be investigated to determine which gives the most reliably measure of functional connectivity. The student will perform a literature review, learn how to use fMRI processing software and analyse the data to examine repeatability before writing a report. This project is particular suited to students with an interest in data analyses on large datasets.



Continuous wave Doppler ultrasound

Supervisor: Dr P Williams



The aim of the project is to build and test a simple continuous-wave Doppler Ultrasound device of the type used to measure blood flow and monitor foetal hearts. You will research appropriate designs for an RF transmitter and audio receiver circuit, which you will build on a breadboard, with the eventual aim of transferring the circuit to Vero board and housing it in a simple case. The transmitter would drive a piezoelectric crystal that emits a high frequency sound signal of which a portion will be reflected back from a moving target to the receiver, which will need amplification. The frequency of the audio signal received will be proportional to the velocity of the target. Once you have established that the circuit is working you will test the system using a Doppler phantom, verify the output, and modify the system to improve the output.



Can we make waveguides with a negative refractive index?

Supervisor: Dr D Beggs

Project No.: 3794 Project Type: PHYS


The speed of light in a vacuum c can never be exceeded, and therefore the refractive index n of a material must always be greater than one (n ≥ 1). Left-handed materials, however, are artificial materials created to have a negative refractive index (n < 0), which gives them unusual and extraordinary optical properties. The refractive index n is made up of two parts - the relative electric permittivity and the relative magnetic permeability and n-squared is the product of the two. From Maxwell’s wave equation and taking the square root, it is easy to see the possibility of negative indices. However, the boundary conditions on Maxwell’s equations require us to choose the +ve root, except in cases where permittivity and permeability are simultaneously negative - then we must choose the -ve root. So-called left-handed materials refract light in the opposite direction to normal, and in 2000, Sir John Pendry showed that they can be used to construct a perfect lens, whose resolution can exceed the diffraction limit.Now our research question is: can we use left-handed materials to construct a waveguide? What would be the properties of such a waveguide, and can we confine light in the waveguide beyond the diffraction limit, similar to the perfect lens case? We are interested in waveguides for integrated photonics - the science and engineering of controlling and guiding light around semiconductor chips. Regular waveguides can only confine light subject to the diffraction limit - further confinement could be beneficial in allowing for miniaturisation of devices and the enhancement of light-matter interactions.In the project you will use Lumerical to simulate and investigate the properties of left-handed materials and their formation into waveguides. Lumerical is a state-of-the-art finite-difference time-domain (FDTD) photonics simulator that solves Maxwell’s equations on a grid of points in space and time. It solves Maxwell’s equations exactly and with no assumptions, in that it quickly converges on the right answer as the grid is made finer. This is a computational and simulation project, but Lumerical can be used as a point-and-click and/or scripted software, and so is suitable for all levels of computer programming experience and ability. Most of your results will be obtained in Lumerical, although you may wish to use Python or Matlab for some basic data manipulation and visualisation tasks.



Evaluation of Monte Carlo methods for simulating diffusion magnetic resonance

imaging




Diffusion Magnetic Resonance Imaging (dMRI) is an imaging technique that allows to characterise brain structures in the mesoscale in vivo and non-invasively. This is done by studying the diffusivity of water molecules within the tissue, which is mostly defined by the surrounding structures. To understand this phenomena in real-scenario situations, it is necessary to perform numerical simulations, for which Monte Carlo methods are generally used. These methods consist of representing each water molecule individually, as well as their random movement and interaction with the surrounding environment (also referred to as Brownian motion).

In this project, the candidate will review different algorithms for performing such computational experiments. The advantages and limitations of each of them will be evaluated. Special attention will be paid to efficient algorithms aimed to reduce the computational burden to a minimum. These methods will be tested in realistic scenarios representing brain tissue in the mesoscale (i.e. at a cellular level). This project is particularly suited to students with an interest in computational physics and its application in neuroimaging. The candidate should be familiar with Numerical Analysis (i.e. attending to PX3143) and programming.



Vessel filtering and segmentation from high resolution magnetic resonance images




Analysis of the human cerebral vasculature is important for the diagnosis of different diseases and syndromes, such as stroke or vascular dementia. To determine pathological changes in the vascular network, the vessel trees need to be segmented and quantified. Magnetic resonance imaging (MRI) is a widely-utilised technique for performing such task. Standard MRI-based methods were shown to capture major cerebral vessels reliably. However, they often fail to detect small vessels, whose contrast is suppressed due to the limited resolution of standard (1.5-3T) MR scanners. This problem can be solved using high field (7T) MR scanners, which deliver higher resolution images in the same amount of scanning time.

In this project, the candidate will implement standard vessel filters for segmenting the vascular network. This will be applied to high-field MR images acquired in CUBRIC. Different algorithms will be reviewed, implemented, and compared. This project is particularly suited to students with an interest in data analysis and image processing. The candidate should be familiar with Numerical Analysis (i.e. attending to PX3143) and programming.

No. of Students:


Getting animated

Supervisor: Dr P D Buckle



Solid state physics can be conceptually difficult. Very often measurements are removed from everyday life experience, and experimental observation is complex or at worst tenuous, and yet solid state research underpins the whole of the information and technological revolution that we have been experiencing for the last 50 years since the invention of the transistor.

This disconnect causes a problem. More and more scientists must be able to justify, at a conceptually simple level, complex ideas that explain advanced research topics. This is not only important for education, but for influencing difficult funding decisions.

However, hope springs eternal. For semiconductor physicists band theory gives us the ideal opportunity to draw pictures and make simple analogies that bring alive physical concepts out of the haze of mathematical formality. However, illustrations, animations, and models must stand up to scientific rigour if they are to be truly successful and stand the test of time.

This project will charge a student with developing a number of activities associated with science outreach, developing illustrations, animations, and with the assistance of School technicians possible physical models that will be used in lecture courses (internal and public), public open days, UCAS visit days, physical science and engineering engagement days, and the School web site. The student is expected to identify and learn appropriate software packages for this activity throughout the year, and develop and be able to explain the physics behind the demonstrations developed.



Magnetic field sensors - can we beat a traditional sensitivity barrier?

Supervisor: Dr P D Buckle and Dr D G Hayes



Magnetic field sensors are important. Did you know your average printer has about 80 just for paper jam detection. The car engine has an increasing number to monitor everything from brake wear to piston motion, and there is immense growth in magnetic field sensors for healthcare applications. Just detecting ferrous metals on people unwittingly entering MRI scanners whilst the field is active is saving countless lives across the globe. As always there are challenges. Greater sensitivity is needed, with better temperature stability, in more robust and convenient packages.

Semiconductor Hall sensors have sold in their billions (conservative estimate), and yet if they could push just a little further in sensitivity they could creep into new markets where the only things that exist are unreproducible amorphous magneto-resistors (AMR), or complex and expensive flux gates. (These devices however can approach the ultimate sensitivity of a SQUID; still used by flying aircraft to sense submarines underwater, they are that sensitive).

One of the most advanced semiconductor materials for Hall sensors is high mobility Indium Antimonide (InSb) quantum wells. They have the highest carrier mobility of all the III-V semiconductors and the lightest electron effective mass (good if you are trying to deflect carriers with a small amount of field, which is what you do in a Hall measurement).

This project will use the Hall effect to characterise some relatively unique InSb quantum well devices. These can then be benchmarked against other devices reported in the literature, and also compared to commercial offerings from companies such as Asahi corp, or AHS Ltd. The aim at the end of the project will be to hypothesise, through understanding of the physics, how to make them better, from the material design to the device construction.



Multi port switching

Supervisor: Dr P D Buckle



All too often, students are fried by the time it takes to pre-qualify devices before measurement (at research level, device yield is low!). This project will look to develop instrumentation to enable automated screening of both Hall and Diode samples. The student will be expected to be proficient with Python and enthusiastic to interact with the electronics workshop. The second semester will be all about putting this system to the test on some real research samples

No. of Students: 1


Maths animations




First year maths students always have trouble grasping a. integration over surfaces and volumes and b. curvilinear coordinates. You will produce some helpful animations to assist in the teaching of these subjects.



Water vortices 1




You will investigate the decay of turbulence by building a shallow water rig with an array of stirrers for creating multiple eddies which are then allowed to die away. You will need to find a way of tracking the motion of the water using tv and frame grabbing software.

Good fluid dynamics/understanding of fourier analysis/programming.



Water vortices 2




You will commission the large water vortex generator and confirm that it generates a vortex with surface shape z proportional to 1/r. You will then attempt to adapt the generator to produce 'free' vortices when the water is allowed to drain out of the tank. If successful you will investigate the formation of the free vortices, the importance of initial turbulence, and the effect of the vortex on the outflow of water.



A study of the intrinsic noise properties in superconducting Kinetic Inductance

Detectors




The ability to detect the packets of electromagnetic radiation (photons) at optical and Near-IR wavelengths is widely used in modern scientific research and allows us to obtain information about faint sources of light ranging from astronomical objects to the single photon quantum dot emitters. To date many single photon counting detectors such as photo-multiplier tubes, transition edge sensors (TES) and avalanche diodes are either unable to resolve the energy of a single photon or cannot be scaled to imaging arrays in a practical way.

The Kinetic Inductance Detector (KID) is a relatively new technology based on superconducting resonant circuits. Here, the absorption of EM radiation alters the physical properties of a superconducting resonator changing its resonant frequency. These detectors have low enough noise to not only allow single photon detection but also measurement of the photon energy at Near-IR and Optical wavelengths. This high sensitivity coupled with simple scalability of pixel number makes KID devices a strong candidate for the next generation of single photon astronomical instrumentation spanning Optical and Near-IR wavelengths.

In this project students will study the device physics of the single photon counting KID and model its performance using a combination of specialist software packages, python written code and existing research data. The performance of fabricated devices will then be compared to theory through a series of experiments measuring real devices. Specifically the student will:

Learn the basic principles of superconductivity relevant to KIDs.Learn the concepts of microwave theory related to the readout of KIDs.Learn how to model single photon events in KID detectors. This project has the potential for some experimental testing of devices but due to the complexity of the equipment used, this work will involve working alongside and assisting research staff.



Animating Schrödinger’s equation

Supervisor: Dr M Elliott



The aim of this project is to solve Schrödinger’s equation in 1D and produce computer animations (gif and/or mpeg) to show the time development of wavepackets. This project involves mathematical methods and computer graphics and requires a good understanding of the physics involved. Programming should be in Python or F90 and run on Unix (or Linux), rather than Windows, to take advantage of the free software tools available. The main objectives of the project are as follows. Devise methods to solve numerically the 1D time-dependent Schrödinger equation. Investigate the best methods for computer graphics/animations using freely-available software. Produce animations to illustrate and interpret some textbook-like examples, such as a wavepacket in the SHO, a particle impinging on a barrier, and tunnelling through a barrier. This project has run several years with some very successful results which give a real feel for quantum effects.

No. of Students: 1


Computer simulation of simple polymeric systems

Supervisor: Dr M Elliott and Dr C C Matthai



The aim of the project is to construct a polymer chain (example - a freely jointed chain) to model protein structures. The structural and thermodynamic properties of these chains will be investigated using both Python and powerful freely-available programs such as VMD (visual molecular dynamics) and NAMD or DLPOLY (for molecular dynamics). The emphasis is on using visualisation techniques to gain an insight into how real protein structures behave. The starting point will be to make simple models to learn to use the programs. Then, we shall set up some freely jointed chain models, where no potential energy terms (atomic forces) need be included. The free energy is determined by entropy alone in this case. There are many interesting basic questions we can try to answer: How is the entropy of a chain defined and measured? What is the rate at which the chain changes between configurations? If we take a single chain, will it "visit" all possible configurations with time, or would we need to start it off in a different initial configuration? This is a relatively new and open-ended project, with room for the student to explore their own ideas.



Daisyworld




AIM OF PROJECT To model daisy world on a computer. OBJECTIVES James Lovelock, famous for the Gaia hypothesis, and others introduced the idea of Daisy world: "Imagine a planet just like Earth, and orbiting a star just like the sun. This imaginary planet has a surface of bare earth, but is well watered and capable of supporting plant growth. It is seeded with daisies of two different colours, one dark and the other light. The star that warms Daisyworld is like our own sun, one that warms up as it grows older. The object of the model is to show that the simple growth and competition for space between the two daisy species can keep the temperature of Daisyworld constant and comfortable over a wide range of radiant heat output from the star." The main objective is to create a mathematical model of daisy world and critically evaluate the results of solving it on a computer. This could include questions of its basic assumptions and dependence of the output on various input parameters. References http://en.wikipedia.org/wiki/Daisyworld http://www.ph.ed.ac.uk/nania/nania-projects-Daisy.html This project has run about three years. It is possible to see some quite advanced modelling of artificial ecosystems, and for example see life-like behaviour with “cellular automata” (i.e. akin to Conway's “Game of Life”).

No. of Students: 1


Dynamics of fractal objects




The aim of this project is to investigate the motion of a fractal object to attempt to determine its fractal dimension. An experiment by Mead et al (Ref 1) casts doubt on an earlier paper (Ref 2) to measure the fractal dimension of crumpled aluminium spheres. The objective is to develop a new method to measure fractal dimensions. The method to be investigated is based on setting up spheres as a torsional pendulum with capacitive motion detection and so finding the moment of inertia without the influence of surface irregularities.

References: (1) Rolling motion and crumpled surfaces Lawrence R. Mead, R. F.Folse, and Anna Cole Am. J. Phys. 63, 746 (1995) (2) A Galilean experiment to measure a fractal dimension F. F. Lima, V. M. Oliveira, and M. A. F. Gomes Am. J. Phys. 61, 421 (1993)



Ice physics




Ice has a number of unusual properties - it is one of the few substances which expands when it freezes for example. This is related to the nature of the hydrogen bonding between the individual molecules and the way the molecules arrange themselves. The aim of this project is to explore the dielectric properties of ice as a function of temperature. This can be done in a remarkably simple way by measuring the frequency dependence of the capacitance of a capacitor with ice between its plates.Experimentally, the student(s) would need to design a good method of freezing the ice whilst avoiding bubble formation, measuring the temperature and taking the data on the computer. However, much of the apparatus is already available for this. It should be possible to deduce the time scale for the ice moleculesto re-arrange themselves in when displaced (the "relaxation time" of the molecules) and how this changeswith temperature.

No. of Students: 1or 2


Molecular dynamics simulation of hard spheres




This is a new project this year. The aim is to simulate the motion of colliding particles using laws of elastic collision – this is basically a form of molecular dynamics (MD). You will model the motion of molecules in a gas as a simple example and extend this to other systems of interest. It involves Python programming and 3D animation, and could result in material useful to the year 2 thermal physics module. The “hard sphere model” you will use has these features: N particles of given masses, given initial positions and velocities, confined in a unit cell. Particles interact via elastic collisions with each other and with the box walls, but travel at constant velocity otherwise. This simple model is ties up with concepts that are met in statistical mechanics. You might study Brownian motion and the energy distribution of particles that arises (Maxwell Boltzmann) or thermodynamic properties like temperature and pressure.



Percolation




This is a mainly computational project to use Monte Carlon (MC) techniques to calculate the resistance of a network of connected resistances. This problem can be solved analytically only in some very simple cases (e.g. if twelve 1-ohm resistors are arranged to form the edges of a connected cube, what is the resistance between the diagonally opposite points?). It is closely related to the general idea of percolation, where points are connected by complex regions of allowed and disallowed paths. The project aims to solve this problem by setting charges off through the network in a random way, then relating this diffusion of charges to conductance. Comparison can be made to actual resistors soldered to form a network. Other aspects of percolation (e.g. cracks in rocks, forest fires, disease propagation) might be examined given time.

No. of Students: 1


Solving Schrödinger’s equation




The aim of this project is to solve Schrödinger’s equation in 1D using the method of expansion. In this method, an eigensolution of the time-independent Schrödinger equation for some complicated potential V(x) is written as a linear combination of eigensolutions of a much simpler potential which are known analytically. This results in a matrix equation which can be solved using available routines from numpy. The technique would be applied to some known problems (e.g. a parabolic well) as a check of the method, before moving on to more interesting problems such as two coupled quantum wells.

Reference: Computational methods in physics, chemistry and biology, Paul Harrison, Wiley (2001)

No. of Students: 1


Can you BUILD a SQUID?

Supervisor: Dr S R Giblin



Aim: To build and test a SQUID.

A superconducting Quantum Interference Device ( SQUID ), is a device that has extraordinary properties. In the superconducting state the behaviour of the electrons can be described by a single microscopic properties. One consequence of this is that the device is extremely sensitive to magnetic field, and can be used as a magnetometer to measure the magnetic properties of materials. In this project we aim to build a SQUID from a piece of Niobium and some standard solder, and test the properties

References.http://dx.doi.org/10.1051/rphysap:019700050103200

OBJECTIVES:i)To understand the basics of how an SQUID works.ii) To fabricate a system to see what we measure.

PROJECT REQUIRMENTS

Students will be expected to attempt to build a system from scratch and/or model the system if two students are on the project. This is a hands on project to build the system, as such skills such as soldering and project planning (and doing!!) are required. This project will develop as far as you push it



Computational modelling of quantum structure self-assembly

Supervisor: Prof D E Jesson



A topical area in semiconductor physics is the creation of novel quantum structures consisting of just a few thousand atoms. Potential device applications include novel lasers, electron spin memory devices and quantum computing. This can be achieved by so-called self-assembly, from atomic beams of atoms incident on surfaces. These structures can take on exotic shapes in the form of dots, rings, multiple rings, molecules and holes. This theory project will model how specific quantum features, such as rings, form. This will involve numerical modelling of surface diffusion equations which describe the reaction of atoms on surfaces. The goal will be to generate computational movies of quantum structure formation dynamics.



Physics of low energy electron scattering from surfaces




This is a theory project to understand how low energy electrons scatter from surfaces and will contribute to the development a new surface convergent beam low energy electron diffraction (CBLEED) technique to probe the nanoscale structure of surfaces. This will provide a new means of obtaining surface space group symmetry and the atomic coordinates of surface reconstructions. We intend to obtain the first experimental patterns using a low energy electron microscope (LEEM) [1]. Low energy electrons are strongly scattered by the surface potential and we will apply a number of modeling approaches to simulate and interpret experimental CBLEED patterns in order to extract nanostructural information. [1]R. J. Phaneuf, and A. K. Schmid, Physics Today, March (2003) 50.



Toy models of surfaces




Surfaces of solids are often thought of as static objects. However, at moderate temperatures they are highly dynamic. Atoms move around laterally on the surface, attaching and detaching from surface steps so that they ‘wiggle’ if looked at closely by surface electron microscopy. An extremely simple but powerful means of modeling this type of behaviour is through kinetic Monte Carlo simulations where thousands of atoms can be included [1]. Surface atoms migrate via nearest neighbour hopping with a site dependent diffusion barrier, taking into account the number of nearest neighbour bonds. This project will set up such ‘toy’ KMC simulations to model the basic properties of surfaces. Depending on the interests of the student(s) the model will be used to investigate dynamical behaviour which could include the growth of nanowires, quantum dots or surface melting phenomena. The project will suit those students interested in computational physics.

[1] An application of KMC to model step density is contained in S. Clarke and D. D. Vvedensky, Physical Review Letters 58 (1987) 2235.



Development of virtual experiments in order to support laboratory learning

Supervisor: Dr S Ladak and Prof C Tucker



Aim: To use python and other programming languages in order to develop virtual experiments to support laboratory learning

The vast majority of today’s laboratory sessions consist of students following set procedures outlined in a laboratory handbook without any prior exposure to the material. In this project the student will use python in order to develop a series of virtual experiments that can be used within the first year laboratory. Depending upon the progress, the python script may be extended to develop fully functional iPhone/android apps that can be used by students to support laboratory teaching.

Objectives:

• Carry out a detailed experimental investigation using first year laboratory equipment.• Using python, model the essential physics of the experiment.• Develop a virtual laboratory interface that will allow future students to perform a digital equivalent of the experiment



Micro-magnetic modeling of three-dimensional artificial spin-ice

Supervisor: Dr S Ladak



Aim: To carry out micro-magnetic modeling of three-dimensional artificial spin-ice

Frustration occurs when all pair-wise interactions within a system cannot be simultaneously satisfied. The phenomenon has an impact across a broad range of disciplines in science and is for example, found to be important in the production of solar flares, folding within protein molecules and bonding within water ice The spin-ice materials are model systems to study frustration and have recently been found to be home to defects that behave as magnetic monopoles.

This project will use micro-magnetic modeling to study 3D nano-magnetic arrays that have the same geometry as spin-ice. Students will carry out studies to assess the extent these micro-magnetic arrays behave as spin-ice.

Objectives:

•Create 3D geometries using CSG scripting language•Mesh the above geometries•Carry out simulation in order to determine minimum energy nano-magnetic configuration •Simulate the response of the magnetisation of the 3D element in response to magnetic fields and determine if defects analogous to the monopoles in spin-ice can be created.



Micro-magnetic modeling of three-dimensional magnetic nanostructures




Aim: To carry out micro-magnetic modeling of three-dimensional magnetic nanostructures in order to visualize their domain structures and their response to an external magnetic field.

The world is now ever-reliant on digital data storage as businesses and consumers store more information. It has been estimated that the total amount of digital information stored worldwide is approximately 300 exobytes and this is set to increase by a factor of 50 in the next ten years (Source: IDC Digital Universe study). Today the vast majority of the worlds information (>40%) is stored on magnetic hard disk drives, and it is fundamental research into magnetic materials that has allowed the massive increase in areal density (Factor of >1000). New technologies such as patterned media and heat-assisted magnetic recording (HAMR) promise to maintain a steady increase in areal density over the next ten years but ultimately the computer hard drive will hit a plateau in data storage due to the fact that data is stored only within two dimensions.

Future technologies based upon magnetic materials, such as magnetic racetrack memory, have been proposed and these rely on magnetic materials that are nanostructured in all three dimensions. In order to understand the potential of such 3D magnetic storage devices, the fundamental physics of how nanostructured magnetic materials behave and interact in 3D geometries is needed.

In this project you will model a variety of three-dimensional magnetic nanostructures that have the potential as elements in next generation magnetic data storage devices.

Objectives:

•Create 3D geometries using CSG scripting language•Mesh the above geometries•Carry out simulation in order to determine domain structure. •Simulate the response of the magnetisation of the 3D element in response to magnetic fields of different directions and magnitudes.



Micro-magnetic modeling of three-dimensional magnetic nanowires




Aim: To carry out micro-magnetic modeling of three-dimensional magnetic nanowires

Magnetic nanowires have been the subject of intense study recently, due to their applications in future magnetic recording technologies. To date, the vast majority of studies have focused on planar nanowires, with rectangular cross-section. This is mainly due to the limitations of fabrication processes, such as electron beam lithography that can only manufacture wires in two dimensions. New lithography technologies now allow the creation of 3D magnetic nanowires, of desired cross-sectional geometry.

This project will use micro-magnetic modeling to study magnetic nanowires of different cross-sectional geometry.

Objectives:

•Create 3D geometries using CSG scripting language•Mesh the above geometries•Carry out simulation in order to determine the micro-magnetic configuration of domain walls in 3D nanowires. •Simulate the response of the domain wall to external magnetic field and determine the cross-sectional geometry that leads to the highest domain wall velocity.



Optical properties of colloidal semiconductor quantum dots

Supervisor: Prof W W Langbein and Dr F Masia



Colloidal semiconductor nanocrystals are of interest both for fundamental physics andapplication. They are synthesized in a one-pot chemical reaction by sequentially addingorganometallic compounds, giving a superb control of the structure in the sub-nanometerlength scale while being relatively simple and cost-effective. In this project the students will study the optical properties, specifically fluorescence and absorbance, of state-of-the-art nanostructures synthesised by our collaborators.

The students will learn (1) about the physics of colloidal nanostructures optical properties(2) how to review the literature on the subject(3) how to keep a laboratory diary(4) how to prepare solid samples for optical studies from the colloidal suspensions we get from thesynthesis group(5) how to operate a micro-spectroscope to measure the room temperature optical properties of the nanostructures(6) how to analyse the measured spectra to retrieve information about peak positions and linewidths as function of the nanocrystal structrue (determined by transmission electron microscopy).



Optical traps




Optical traps are scientific instruments where a focused laser beam is used to hold and move microscopic dielectric objects in solution. Optical traps are widely used for biology studies and in biosensing. In this project the students will use an optical trap for microscopic dielectric spheres in liquid and they willinvetsigate the trap force using dielectric microspheres of different material in liquids of different viscosity.

The students will learn (1) about the physics and the design of an optical trap set-up(2) how to review the literature on the subject(3) how to keep a laboratory diary(4) how to prepare the solution of dielectric spheres(5) how to operate the optical trap set-up(6) how to analyse the measured data to retrieve information about trap force and compare it with theory



Optical traps and position readout of trapped particles




Optical traps are scientific instruments where a focused laser beam is used to hold and move microscopic dielectric objects in solution. Optical traps are widely used for biology studies and in biosensing. In this project the students will characterize a three-dimensional position readout with nanometresensitivity for microspheres held by an optical trap and to characterise the optical trap force and the viscosity of the liquid using the measured Brownian motion of themicrospheres.

The students will learn (1) about the physics and the design of an optical trap set-up and of the position readout(2) how to review the literature on the subject(3) how to keep a laboratory diary(4) how to prepare the solution of dielectric microspheres(5) how to operate the optical trap set-up(6) how to analyse the measured data to retrieve information about trap force and liquid viscosity and compare with theory.



Nanostructured materials as potential photocatalysts for water treatment

Supervisor: Dr S A Lynch



Water pollution is a global problem. Compounds including natural organic matter and synthetic organic micro-contaminants, for example, hydrocarbons, pharmaceuticals, endocrine-disrupting compounds like polychlorinated biphenyls, fertilizers and pesticides, are released constantly into the environment by industry, households, and agriculture. Conventional wastewater plants help remove most of the pollutants via regular and cost-effective treatment steps like sedimentation, filtration, and biological processes, all of which are deemed relatively effective for the treatment of wastewater. However, biologically toxic and non-degradable organics can often still remain.

Advanced treatment processes such as activated carbon and advanced oxidation processes are slowly being adopted; but these can be expensive to run and result in increased water costs. Nano-structured materials have a number of important characteristics are potentially useful for this application. In particular, the ratio of surface area to volume for nano-materials tends to be very large. For many catalysts, chemical reactions become enhanced near the catalyst surface, so that maximising the available surface area for this application is essential.

It has long been known that certain natural occurring microcrystalline materials such as the mineral titania (titanium dioxide) can act as catalysts in the presence of sunlight, or more precisely ultraviolet light. It is now understood that this photocatalytic effect comes about because titania is a wide band-gap semiconductor. Semiconductor photocatalysts are now beginning to be used to generate reactive oxygen species for advanced oxidation processes in water treatment technology. This has the potential to become a cheap and energy efficient method for purifying water.

In this project the student will study the photocatalytic properties of titanium dioxide thin films. Methylene blue, which is a non-toxic intense blue organic dye, will be used as a test model pollutant. The project will involve building a an experimental test rig to monitor the colour change of the model test pollutant as it degrades in the presence of UV light and the titanium dioxide thin film catalyst.



Analysis of chaotic motion

Supervisor: Prof J E Macdonald



A chaotic system undergoes motion that depends sensitively on its initial conditions. It is well illustrated by a double pendulum, in which the lower pendulum pivots around the base of a swinging upper pendulum. Previous students have built a double pendulum in which the motion of both pendula can be recorded remotely using a pair of circular potentiometers. The motion can then be explored as a function of initial conditions, driving amplitude and frequency etc. The dynamics of the pendulum can also be explored computationally by developing fairly simple algorithms to predict the motion for a similar range of parameters. (This aspect can easily be developed from an elementary understanding of Python programming.) The project is ideally suited to a pair of students working together on the experimental and computational aspects. However, it can also be undertaken by individual students working on either component of the project.



Computer-based demonstrations for thermal and statistical physics

Supervisor: Prof J E Macdonald



Thermal and statistical physics provides a stimulating playground for developing computer simulations that illustrate the principles and enlighten student learning. One example is the development of molecular dynamics simulations of solids, liquids and gases, which can be achieved with moderate computational skills based on Python programming. The project has considerable scope for developing simulations in either thermal physics or in the applications of statistical mechanics. It is suitable for one or two students with an interest in developing teaching or research tools.



Investigations of complex networks

Supervisor: Prof J E Macdonald and Dr C C Matthai



Complex networks are characterized by highly heterogeneous distributions of links. The structure of these nets can be characterised by several measures including mutual information and generalised entropies. These measures may be computed for a number of real networks and analytically estimated for some simple standard models. The main objectives of this project are to gain an appreciation of complex networks, to gain experience in constructing computer codes to simulate complex networks and to develop and understand the analytical techniques used in characterising these networks. Skills: develop programming skills in JAVA, C++ or Python.



Percolation conduction pathways in 2 and 3 dimensions

Supervisor: Prof J E Macdonald and Dr M Elliott



Transport in disordered media attracts much attention due to its broad range of applications. Examples include flow through porous material, oil production, and conductivity of semiconducting materials or metal-insulator mixtures. In this project, we model this behaviour by the conduction of electrical current through a random network that becomes increasingly disordered. Initial studies will involve carbonised paper with later work aimed at developing percolated blends of onrganic conductors and insulators. For two students, there is scope for developing numerical models to compare with the experimental data and to explore the range of underlying behaviour.



Computer simulation of physics problems using C++/Java.

Supervisor: Dr C C Matthai



The aim of this project is to carry out computer simulations of physics problems in Mechanics, Electromagnetism Quantum Mechanics and Statistical Mechanics using the C++, Python or Java programming languages. It is envisaged that successful projects will result in the construction of applets which can be used as learning tools. Skills: Students taking on this project can develop their programming skills as well as learning C++, Java, Python and gaining experience in visualization.



Computer simulation of spin models




In this project you would be expected to gain an understanding of phase transitions using simple spin model systems. Both analytical and computational methods will be applied to solve these and more advanced model systems. The main objectives are to gain an understanding of phase transitions in physics, to write computer programs to simulate a spin system which can undergo a phase transition (e.g. The Ising model), and to perform computations on the model and to extract the critical exponents. Skills: Students taking on this project can develop their programming skills in C++, JAVA or Python.



Phase transitions and critical phenomena




The aim of this project is to develop an understanding of phase transitions and critical phenomena. In this project you would undertake studies of simple systems showing critical behaviour (eg, magnetism, liquid-gas transition) and extend these to investigate other systems in different areas of physics or in other disciplines like economics or bio-systems. The main objectives are to learn about phase transitions, to solve simple model systems which undergo phase transitions, and to construct models of other more-complicated systems which can be solved analytically or computationally Skills: analytical skills, object-oriented programming skills in JAVA, C++ or PYTHON.



Simulation of gas particles in a container




The aim of this project is to simulate the motion of 20 differently massed particles in a one-dimensional box ( and later in 2-D and 3D boxes). The simulation output every dt time steps is recorded with a view to determining:_ a) the average velocities of the particles as a function of mass; b) the momentum distribution of the particles; c) the relationship between the particle positions and their momenta. Although the simulations can be run using Fortran code, it is envisaged that a C++, Python or Java code could be developed so that a visual representation of simulation can be observed. Skills: Apart from reinforcing their understanding of statistical mechanics, students taking on this project can develop their programming skills as well as learning C++ and gaining experience in visualization.



Nano-structuring: tool for manipulating light emission from semiconductors

Supervisor: Dr S Mokkapati



Nanotechnology has evolved as a powerful tool in the last decade to manipulate interaction of semiconductor materials with light. Nanostructured semiconductors may absorb and emit light more efficiently than a bulk, planar piece of semiconductor. Thus, they have the potential to make efficient solar cells and lasers. The project aims to design semiconductor nanostructures to achieve desired light emission characteristics. Initial aim would be to control the direction and polarization of light emission from the semiconductor. The project may be extended to design laser cavities using nanostructured semiconductors, and demonstrating fully functional devices.This is a computational project. Student will learn to use MATLAB and a commercial simulation software, Lumerical FDTD solutions. Training on both will be provided.

No. of Students: up to 4


Eigenmodes of a photonic crystal slab

Supervisor: Dr E A Muljarov



The aim of this project is to study optical properties of a photonic crystal slab (PCS), calculating light resonances of this system. They are mathematically described by resonant states (RSs) which are the eigenmodes of Maxwell’s wave equation satisfying the outgoing wave boundary conditions. To make calculations as simple as possible, a one-dimensional PCS - a periodic array of long dielectric or metal stripes - will be considered and a model of infinitely narrow slab, with the material presented by delta functions, will be used. An analytical work on solving Maxwell’s equations for a homogeneous dielectric slab and then for a PCS will be followed by a numerical solution of transcendental algebraic equations and diagonalization of matrices, in order to find the light dispersion and eigenmode frequencies. In addition to this, or in parallel (can be done by another student), reflection, transmission and scattering of a plane wave in such structures will be calculated, partly analytically, partly numerically, and the spectral position and linewidth of resonances will be compared with the complex frequencies of RSs. Depending on the number of students involved, the above problem can be solved for both normal and non-normal incidence of light, as well as for both polarizations of light - transverse electric and transverse magnetic.



Light eigenmodes in optical fibres and toroids




In this project, students will be studying light quantization in fibre optic cables. All types of light modes in cylindrical dielectric fibres will be considered, including the well known, strongly localized waveguide modes, yet unknown weakly localized modes, and poorly studied, delocalized Fabry-Perot, leaky and whispering gallery modes. All these types of modes will be calculated for different values of the light propagation wave vector along the fibre. Part of the work will be done analytically by solving Maxwell’s wave equation for a dielectric cylinder with the help of special functions (cylindrical Bessel and Hankel functions). A transcendental equation for the optical modes will be then solved numerically by the Newton-Rawson method. The quality factor of modes will be studied as functions of the propagation wave vector and mode frequency.

Additionally, some of the light modes of a toroid resonator can be found approximately, using the solutions obtained for an ideal cylinder. Students will be able to use some material from a similar project done in the previous year.

No. of Students: 1


Resonant states in graphene




The aim of this project is to learn the concept of resonant states (RSs) and to find RSs of a quantum-mechanical system described by the relativistic Dirac equation. The latter is relevant to a description of electronic states in so-called Dirac materials, such as graphene, narrow band semiconductors, or some specific semiconductor heterostructures. RSs for a 1D rectangular quantum well potential in graphene will be calculated and studied in this project. Mathematically, RSs of such a system are the discrete eigen solutions of the Dirac wave equation satisfying outgoing wave boundary conditions. They usually include bound/localized states as a small subgroup and provide a natural discretization of the continuum spectrum. The RSs describing the continuum have complex eigenenergies that effectively accounts for their metastability and decay in time. Examples available in the literature include RSs of non-relativistic particles in simple 1D potentials. RSs of graphene are, however, not yet known.

No. of Students: 1


Resonant states quantum in mechanics: the Coulomb potential




The aim of this project is to learn the concept of resonant states (RSs) and to find RSs of a non-relativistic particle in a 3D Coulomb potential. Mathematically, RSs in quantum mechanics are the eigen solutions of the Schrödinger equation respecting outgoing wave boundary conditions. They usually include bound/localized states as a small subgroup and provide a natural discretization of the continuum spectrum. The RSs describing the continuum have complex eigen energies that effectively accounts for their metastability and decay in time. Examples available in the literature include RSs in simple 1D potentials. RSs derscribing the continuum spectruum of the 3D Coulomb problem are not known. They will be calculated and studied in the present project.



Reliably measuring functional connections in the brain

Supervisor: Dr K Murphy



Functional magnetic resonance imaging (fMRI) uses the magnetic properties of blood to measure neural activity in the brain. When neurons are active, they consume oxygen causing blood vessels in the region to dilate to bring more blood. This is the basis of the fMRI signal. Recently, researchers have been using these signals to examine the brain "at rest". Brain regions whose signals fluctuate in the same way over time are said to be functionally connected, that is, they form part of a neural network in the brain that performs a specific task. However, because the fMRI signals are not a direct measure of neural activity, they are susceptible to many confounds that affect the blood signal: motion, cardiac, respiration, blood pressure, etc. These in turn affect the measure of connectivity - how strongly the regions are thought to be connected.

In this project, the student will examine recently collected data. The effects of various preprocessing steps designed to limit noise will be investigated to determine which gives the most reliably measure of functional connectivity. The student will perform a literature review, learn how to use fMRI processing software and analyse the data to examine repeatability before writing a report. This project is particular suited to students with an interest in data analyses on large datasets.



Crystal surface optimization

Supervisor: Dr J Pereiro Viterbo



The project consists on the experimentation with crystalline surfaces. The goal is to optimize surface properties for epitaxy and nanostructure nucleation. The project will include chemical processes and thermal treatments, studying for example step bunching and planarization of surfaces.

No. of Students: 1


Physics demo / outreach

Supervisor: Dr J Pereiro Viterbo



The goal of the project is build physics demos to start a collection that we can tour to schools or science events. The project will include to search for these events, make a calendar with all the yearly events and show the demos that have been fabricated to the general public.This is a very engaging way to do outreach with kids and general public. Suggested demos may be: Magdeburg hemispheres: https://www.youtube.com/watch?v=k1-XLjACzssAngular momentum conservation: https://www.youtube.com/watch?v=5cRb0xvPJ2MVan der Graaf: https://www.youtube.com/watch?v=1jP_D0S2CtYChladni plates: https://www.youtube.com/watch?v=YedgubRZva8Air propulsion: https://www.youtube.com/watch?v=R625vwA4jpQPendulum waves : https://www.youtube.com/watch?v=yVkdfJ9PkRQMagnetic induction : https://www.youtube.com/watch?v=NqdOyxJZj0U



Degradation mechanisms in quantum dot on silicon lasers

Supervisor: Prof P M Smowton and Dr S Shutts



INTRODUCTION: Future integration of photonics and electronics will probably proceed via the growth of III-V materials, favoured for photonics, on silicon. Due to the different lattice constants and thermal expansion coefficients of the III-Vs in use and silicon it is expected that degradation of device performance will be an issue. Here we will explore the mechanisms causing degradation in lasers grown on silicon substrates.

AIM: To quantify and understand the main degradation mechanisms in lasers grown on silicon substrates.

OBJECTIVES: - Familiarisation with standard laser diode characteristics and characterisation techniques.- Perform automated device measurements.- Analyse data and suggest degradation mechanisms and methodologies to test these hypotheses.

LEARNING OUTCOMES: Understanding of laser physics and semiconductor physics, measurement techniques



Developing Generic Integrated Photonics

Supervisor: Prof P M Smowton and Dr S Shutts



INTRODUCTION: Photonics is now being developed on compound semiconductors replicating many of the features of bulk optics. This opens up the possibility of entire optical systems on a chip and for the future rapid development of photonics along the lines of electronics and the integrated circuit which revolutionised computing in the last century. The new Photonic Integrated Circuits (PICs) will produce similar changes over the next 50 years if the much wider and richer capability can be understood and configured in a manufacturable generic integrated photonic circuit. AIM: To design, simulate, make and characterise photonic integrated circuits (PICs).OBJECTIVES: Familiarisation with the physical mechanisms used in optical components and transfer to compound semiconductor form.Design and simulation, using existing software, of an exemplar PIC.Characterisation of device made and suggestions for design improvements.

Learning Outcomes: Understanding of optical and laser physics, semiconductor physics, simulation and measurement techniques

No. of Students: 2


Minimising divergence in integrated semiconductor lasers

Supervisor: Prof P M Smowton and Dr R Thomas



INTRODUCTION: Laser diodes in integrated systems require minimal divergence of output light to maximise optics free coupling. However, typical laser waveguides have dimensions of order the wavelength of guided light leading to appreciable divergence.

AIM: To design and demonstrate an approach to minimise divergence of output light without significantly increasing operating current or degrading other aspects of device performance.

OBJECTIVES: - Familiarisation with laser waveguides and design software. - Understanding laser device physics and how the waveguide affects device performance. - Produce design or designs of low divergence structures. - Measure performance of fabricated devices and iterate.

LEARNING OUTCOMES: Understanding of laser physics and semiconductor physics, measurement techniques



Vertical Cavity Surface Emitting Lasers for Miniature Atomic Clocks

Supervisor: Prof P M Smowton and Dr L Kastein



INTRODUCTION: Miniature coherent population trapping (CPT) based clocks use the following fundamental physics package components: A single mode laser diode (typically a VCSEL), beam conditioning optics such as an ND filter and a quarter-wave plate, a cell containing a vapour of alkali atoms (generally atoms that have a three-state lambda energy structure such as caesium or rubidium), and a photodetector. The laser diode operates at the D1 resonance and is modulated at half of the hyperfine ground states separation frequency (4.6 GHz for caesium, 3.4 GHz for rubidium), such that a superposition of the two ground states being resonant to a third state is achieved, enabling coherent population trapping of the atoms in the third state and causing optical transparency, i.e. the atoms no longer absorb the light. As the modulation is swept through this feature, a spike in the optical transmission through the atoms is detected by the photodetector positioned at the other end of the cell, providing a means to identify the precise resonant frequency of the atoms and thereby serving as a stable frequency discriminant.

AIM: To develop VCSELs for applications in atomic clocks.To understand the properties of the laser light source and how these are controlled through design.

OBJECTIVES: Develop understanding and familiarisation with some important laser characteristics.To become proficient in and understand laser and optical beam characterisation techniques. To make suggestions for improvement to the design of the VCSEL device to optimise performance characteristics required in atomic clocks.

Learning Outcomes: Understanding of laser physics and semiconductor physics, measurement techniques

No. of Students: 2


The physics of sport




This project covers a range of possibilities all aimed at understanding the physics behind bat-ball sports. Over recent years I have run projects investigating "bats" and the "bat-ball" collisions that occur in cricket; hockey and golf. Three main experimental approaches are available: investigating collision efficiencies using a 1D video camera; investigating vibrational modes using microphones; and investigating inelastic losses using an infra-red camera.

One important concept we would like to understand is the "sweet spot". Strike at the sweet spot and the ball will travel "for miles"; strike badly and the ball will dribble back to the bowler (in cricket) and your hands will hurt from the vibrations transmitted to the handle. More technically what's behind the sweet spot is the "collision efficiency" discussed above and the "centre or percussion" which relates to the solid body of the bat. Beyond that off-centre collisions, vibrational modes, recoil, how the bat is held, the characteristics of the blade or shaft etc are all important.

Investigation focused on other sports is possible (I’m open to suggestions) but a practical line of investigation must be identifiable.

The project is suitable for experimentally minded students willing and able to model their data.

No. of Students: 1 to 6 (students working in pairs is preferred)


Thin Film Analysis Using X-Ray Fluorescence




The aim of this project is to explore the potential for X-ray fluorescence (XRF) in the characterisation of film films of thicknesses down to nanometre dimensions.X-ray fluorescence (XRF) is a non-destructive analytical technique often used to determine the elemental composition of materials. Fluorescent X-rays characteristic of the elements present are emitted from a sample when it is excited by a primary source. The interest in measuring the properties of "thin films" results from the efforts of research groups in this School to produce and make use of a wide variety of thin films (e.g. Cu, GaAs, diamond, Nb..) for a wide variety of purposes (e.g. magnetic and semiconductor devices, infra-red detectors and filters..). To satisfy their purpose the films need to have the "correct properties" an important one of which is their thickness. To ensure that they are doing it right a range of characterisation techniques are applied - at the moment XRF is not one of the techniques and the question is to determine whether it could be.Bearing in mind that X-rays are weakly attenuated by matter XRF would be expected to struggle for signal as films become thinner. Consequently two important questions (aims) are immediately to the fore: (i) How accurate is the technique?; (ii) Is it sensitive enough for nanotechnology applications?The project will involve careful experimentation and modelling of the data produced.As the equipment required is used in the undergraduate laboratory some flexibility in approach will be required.Suitable for 1 or 2 students (pairs of students preferred)



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