School of Physics & Astronomy
   
   
  

UG Summer Scholarships

A limited number (typically a dozen) of paid Summer scholarships are

offered to Physics undergraduate students between their 2nd and 3rd year or 3rd and 4th year of their course to enable them to undertake a research project with a research group in the School. The scholarships pay approximately £200 per week and are between 8-10 weeks in duration (start date to be mutually convenient to Academic and Student).  The selection process takes place in January/February each year.

Complete the FORM and email to Olga Fernholz by 1 February 2018. Studentships pay approximately £200 per week and are between 6-8 weeks.  Start dates are at mutually convenient times for students and supervisors.


Professor Omar Almaini
Testing models for galaxy quenching

The most massive galaxies today are typically “red and dead”, and undergoing very little new star formation. Further study has revealed that these galaxies formed rapidly in the early in the Universe, but at some stage their star formation was abruptly extinguished (“quenched”). A number of mechanisms have been proposed to explain this quenching, of which arguably the leading contender is feedback from supermassive black holes. An alternative scenario suggests that intense star formation led to the ejection of gas from early galaxies in the form of high-velocity winds, removing the fuel supply for new stars. To date, however, there is little direct evidence to support either of these scenarios.

The aim of this project is to directly test competing models for galaxy quenching, using the latest data from the Ultra-Deep Survey (led by Nottingham). Deep X-ray observations allow us to identify the galaxies hosting accreting supermassive black holes, while our unique deep imaging and spectroscopy allows us to identify galaxies at various stages in their evolution, from those that are actively forming stars to the systems that ceased star formation long ago. The aim of the project is to compare the large galaxy samples we have assembled with the predictions of quenching models, using statistical methods to determine the most likely mechanism for switching off star formation.


Dr Keith Benedict
Interaction Effects in Topological Metals

There is considerable interest at present in the behaviour of materials with topologically non-trivial band-structures. While much is now known about topological insulators and topological superconductors1, less is known about systems with strong interactions. The aim of this project is to study a lattice (tight-binding) model of bosons with local interactions and non-trivial kinetic energy terms (similar to the effect of a magnetic field on charged particles) using the density matrix renormalization group method2. This is a numerical approach well-suited to quasi one dimensional systems which is known to give extremely accurate results in such strongly correlated systems. In the absence of interactions this model is exactly solvable. In the absence of the pseudo-field it is known to have a sequence of insulating phases separated from the weak-coupling superfluid phase by a set of quantum phase transitions. The aim of the project will be to map out the phase diagram of this system and to compare it with more straightforward mean field approximations. 

1.           Hasan, MZ and Kane, CL, Reviews of Modern Physics, 82, 3045 (2010)

Schollwöck, U, Philosophical Transactions of the Royal Society A, 369, 2643 (2011) 


Dr Simon Dye
Systematics in Strong Gravitational Lensing

Modern techniques for computationally modelling strong gravitational lenses reconstruct an image of the background source being lensed. There are many 'off the shelf' routines available for the general user which compute a best fit lens model and a background source surface brightness map given some basic input quantities. These codes give an indication of the statistical error on derived lens model parameters and reconstructed sources but ignore any potential systematic errors.

There are many sources of systematic error that can creep into lens modelling, such as an inaccurate point spread function, a lens model that doesn't describe the true lens mass distribution and the way in which the source map is defined. These systematics have never been investigated in a dedicated study before but are potentially significant and therefore very important to understand and quantify. This is especially true at this moment in time as the astronomical community prepares for an increase in the number of known strong galaxy lens systems by several orders of magnitude from forthcoming facilities like LSST and Euclid.

This project aims to quantify these systematics. It is computational in nature and will involve running existing lens modelling code. Applicants should ideally be competent programmers. 


Prof Juan P Garrahan and Dr Adam Moss
Deep learning applied to statistical physics

Deep learning has recently revolutionised fields such as computer vision, speech recognition, natural language processing, search, and many more. It is a class of machine learning which aims to "teach" a computer an abstract representation of data. This representation is encoded by the weights of a neural network (NN), which consists of many layers of non-linear processing.

Learning can be supervised, partly supervised or unsupervised. In supervised learning training data is provided with known labels, whereas in unsupervised learning data is unlabelled and the machine must try and find hidden structure in the data itself. It is not yet fully understood why deep learning is so effective. It has been shown in computer vision problems, for example, that deep neural networks learn better representations of data than wider, shallower networks.

This project is about applying deep learning to problems in statistical mechanics. One such area is the automatic classification of features in systems undergoing phase transitions. Questions to be addressed include: can one train (via supervised learning) a NN to classify microstates belonging to distinct thermodynamic phases, to identify the features that distinguish such phases, and to anticipate the critical values of parameters that control the transitions; and what are optimal NN architectures for optimal performance of these tasks. 

This project has a mixture of analytical and computational work, and requires a good grasp of thermal and statistical physics and of computer simulations.

See e.g. J. Carrasquilla and R.G. Melko, “Machine learning phases of matter”, Nature Phys. 13, 431 (2017).


Prof Penny Gowland
Alternative methods for presenting scientific reports

This project aims to answer the question, can the results of a scientific investigation be shared effectively with the scientific community through the medium of video (or similar), rather than text? If so, is it possible for students with dyslexia to be assessed by alternative methods rather than written reports?

This project will involve converting undergraduate physics reports into a recorded verbal/visual (video) report and comparing the two to see if they both contain the same information and they both communicate research findings equally clearly and efficiently. This will be judged by qualitative assessments including comprehension exercises performed on members of University staff and students (with and without dyslexia themselves). The time taken to interpret the work will also be considered.

The development of the new methods of presentation will be informed by education videos on YouTube and the peer reviewed JoVE journal which uses videos to describe methodology.

The process of constructing the video will be documented to allow the process to be used and developed by other students in the future.

 


Prof Gowland and Dr Shah
Placental MRI

We have many methods of studying haemodynamics within the placenta. We want to be able to use these to test mathematical models of blood flow within the placenta.

This project will investigate how different MRI movement encoding schemes provide sensitivity to different types of motion (e.g. linear acceleration, rotation).

It will involve numerical simulations of different encoding schemes on different types of movement. This will include considering limits on the possible MR sequences due to hardware constraints in different scanner systems. These resulting schemes will be tested in phantoms and also in vivo in pregnant women where appropriate.

It is expected that this project will form part of a collaboration with groups modelling blood flow within the placenta.


Dr Lucia Hackermueller
Creating clouds of cold atoms in an optimised system

The development of laser cooling techniques has led to a rapid growth of the field of cold and ultracold atoms, which deals with (mainly alkali) atoms at micro- and nanokelvin temperatures. At these record low temperatures, quantum phenomena are important and can be directly observed. Cold atoms are interesting quantum systems, because they are comparatively easy to describe and model and at same time can be used to study genuine quantum effects.

In that sense cold atom systems can be applied in the area of “quantum technologies”, where quantum effects are used for precise sensing, imaging, information processing or quantum computing. A work horse for cold-atom and ultracold atom experiments is the magneto-optical trap. We have developed a system that is small, light-weight and uses optimised coils for the production of magnetic fields, a chamber based on 3D-printing and simplified electronics. Our system is an ideal starting point for a portable quantum-technology device.

The task for the summer project will be to learn how to operate it and create a cloud of cold Rubidium atoms at microkelvin regime and characterise the performance of the system. Several parameters will be tested for optimal trap loading with respect to a large number of atoms as well as reaching low temperatures. The project will involve work on the laser system for the cooling light, including spectroscopy, locking electronics and computer control of the experiment.

This project will enable insights into the everyday life in an experimental lab and will be a great opportunity to learn a wide range of experimental techniques from adjusting and dealing with optics, atomic physics, electronic circuits and process control to data acquisition. 


Dr Philip Hawker
Getting students to love first year labs

Laboratory classes are not generally popular among students – many transfer to theoretical courses with no laboratory sessions after year 1.  A-level practical work has changed recently and we need to think about how to smooth the transition to degree level laboratory classes. These are the questions this proposed study will address. Is our practical curriculum up to date and relevant? Can we use new technology e.g. video in the classroom, to aid learning and make the classes more engaging and interesting? Should we teach skills, such as the use of an oscilloscope, explicitly or should these skills be embedded as part of an experiment? Are there diversity issues? Should we have defined practicals or open-ended investigations or both? How can we make the lab fun?

The study will take place in Semester 2.

- Focus groups and student survey, plus discussion involving students, staff, demonstrators and technical support staff, to assess current state of provision/level of engagement.

- Review of relevant literature on approaches taken elsewhere.

We are looking for a third year undergraduate with an interest in education to undertake a large part of the information gathering, analysis and report writing in June/July of the Summer vacation.


Dr Matteo Marcuzzi and Professor Igor Lesanovsky
Non-equilibrium phase transitions in Rydberg quantum simulators

Interacting gases of cold atoms constitute a versatile platform for the exploration of many-body physics and the emergence of collective phenomena. In particular, atoms which are laser-excited to high lying Rydberg states are currently in the focus of intense theoretical and experimental investigation. Currently, they represent one of the most modern manifestations of so-called quantum simulators.

The goal of this project is to study ensembles of such Rydberg atoms in a parameter regime where this system displays a non-equilibrium phase transition. This means that the stationary state of the system will undergo a sudden change upon changing an external parameter. You will formulate the equations of motion of a Rydberg gas in the presence of laser excitation, interactions as well as the coupling to environment and calculate the time-evolution as well as the stationary state. To this end you will employ numerical and analytical, e.g. field-theoretical, methods. The scope of the project is relatively broad, which means that the exact setting to be considered will be discussed in an initial meeting.

Depending on the progress this project may involve the modelling of an experiment.


Dr Yong Mao
Physical Modelling of Urbanization

Urbanization is the process by which towns and cities are formed. The United Nations estimated that around half of the world's population lived in urban areas at the end of 2008, and that portion will rise to around 75% by 2050. Understanding and sustaining the process of urbanization is a key challenge for humanity.

Following recent projects (e.g. InSmart and Leverhulme), substantial progress has been made in understanding the energy use by the city of Nottingham, which was a key case study city. A basic zonal model (similar to the physical Ising/Potts model) has been developed based on the land use data for Nottingham. This project seeks to develop a general inference model to examine systematically the correlation between land usage and other available data such as population distribution and accessibility to services. Indicators relating to sustainability can then be deployed to search for the optimal urban form. Our aim is to extend the existing understanding of physical systems to inform a sustainable urban design.

1. http://www.nottingham.ac.uk/research/groups/lucas

2. http:/www.complexcity.info/

3. https:/en.wikipedia.org/wiki/Urbanization


 

Dr C J Mellor
Electron Beam Lithography Proximity Correction Software

A new electron beam lithography facility has been established in the Nanoscale and Microscale Research Centre (NMRC) in a building adjacent to the Physics Building. The lithography tool, a nanobeam nB5, is capable of writing features smaller than 20nm and ‘stitching’ writing fields together with a 20nm precision over the 200mm diameter sample holder.

There are several different research projects that are exploiting the new facility including photonic crystals, 2D materials, submicron optical waveguides and plasmonics. For the most demanding lithography tasks the structures we are writing are complex and the dimensional tolerances are a few nm. To reach this level of performance we need to correct the electron exposure absorbed by the resist to take into account the electrons scattered by the substrate, in addition to the direct exposure due to the electron beam. The exposure of the resists by the scattered electrons is known as the proximity effect.

The aim of the summer project is to write computer programs that will read in the data files that define the geometrical shapes of the pattern, correct the exposure for the proximity effect and then prepare the corrected data files in a form that the lithography tool can use. During the project we will write test patterns to verify that the corrected exposures are working as expected. The summer student will work as part of the electron beam lithography team and will learn more about the exciting projects we are involved in.


Dr James Sharp
Mechanical vibrations of liquid crystal droplets

Liquid crystals (LC) exhibit phases in which the molecules have positional disorder, but have some degree of orientational order. The rod-like nature of the molecules means that the flow characteristics of these materials are highly dependent on the direction in which they are sheared (relative to the orientation of the molecules). As such they display some interesting rheological properties when deformed in different directions.

The vibration of microlitre liquid droplets has been shown to be a novel way to extract information about the surface tension and rheological (flow) properties of simple liquids [1] and viscoelastic fluids [2]. In this project you will extend this previous work in an attempt to study the vibrational response of LC samples. You will use electric fields and/or mechanical impulse techniques to excite the vibrations of microlitre LC droplets. The vibrations will be monitored using a novel laser light scattering technique and by imaging with a high speed camera. You will study the contact angle dependence of the vibrational properties LCs and determine how wetting effects influence their properties.

[1] Temperton et al. Eur. Phys. J. E (2015) 38: 79 DOI 10.1140/epje/i2015-15079-2

[2] Harrold et al, Langmuir (2016), 32, 4071−4076 DOI: 10.1021/acs.langmuir.6b00779


Dr Mike Smith
Fracture Propagation in a Drying Colloidal Film

The drying of a fluid containing small particles is of particular importance to the coatings industry (paints, glazes, inks) but is also important for the manufacture of advanced materials such as photonic crystals. Drying results in the build up of stress in the film which often leads to cracks which propagate through the thin film. In a controlled geometry, arrays of parallel cracks follow the drying front. Whilst crack propagation can occur smoothly and continuously, a number of studies have reported that cracks may also propagate by rapid jumps to a new location followed by a period of stasis before again rapidly moving - “crack hopping”. Despite being reported and studied in the literature for more than 15 years, it is still not clear why crack hopping occurs.

In this study we will use optical microscopy to make measurements of crack propagation. We have discovered a system of silica particles which under different conditions display either smooth propagation or crack hopping. The project will seek to understand which physical parameters control the lengthscale of crack hopping and how crack hopping is related to the appearance of microbranching.

The project will involve some computer image analysis to analyse the shapes of cracks as well as experimental skill to perform measurements of crack propagation.


Dr Mike Smith
Pneumatic resonances in a blocked urinary catheter

Urinary catheters are commonly used in healthcare for patients suffering from urinary tract complications often brought about by cancer. These simple devices consist of a tube passed through the urethra into the bladder. However, these devices can frequently become blocked due to the crystallization of salts or the accumulation of protein aggregates, blood plasma etc. Currently, this requires the catheter to be replaced causing great discomfort to patients.

This project will explore novel strategies to unblock the catheter without its removal. In particular the use of small pressure pulses applied to the tube at different frequencies near resonance will be investigated. The project will aim to gradually build and refine an experimental mock-up of the clinical problem, investigate the feasibility of the proposed solution and begin to develop a prototype device.

 


 

 

 
 

School of Physics and Astronomy

The University of Nottingham
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Nottingham NG7 2RD

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