At Sussex, you learn from experts working at the forefront of physics. This means you study modules based on the latest research, whilst exploring the fundamental laws of physics. In the research placement programme, you will have the opportunity to directly experience world-leading physics research through paid placements in active research groups during the summer holidays. This unique experience will give you a significant advantage when you apply for jobs, either in academia or in industry.

Exploring the Quantum Vacuum: Understanding the Lamb shift caused by vacuum fluctuations in various systems

Faculty advisor: Claudia Eberlein

Quantum mechanics predicts the energy levels of quantum systems, but precision measurements show deviations from the predicted energy levels which are due to the interaction with the fluctuating quantum electromagnetic field. Even in the so-called vacuum state where there is no net field and no photons present, there are always fluctuations. These virtual photons affect different quantum states in different ways, thus causing differential shifts which are measurable. The student will learn the basics of field quantization and the conventional Lamb shift of atomic energy levels. The aim of the project is then to understand how the Lamb shift could be described in other systems like qubit circuits.

See the following articles for more information: Resolving Vacuum Fluctuations in an Electrical Circuit by Measuring the Lamb Shift (Fragner et al.); Lamb shift spotted in solid qubit.

Transferable skills: The student would learn research methods and skills that are useful in most areas of theoretical physics, such as the building of a theoretical model from a much more complicated physical background and the application of a wide range of mathematical tools.

Other experiences: Most of the background knowledge to be acquired during this project would give a headstart to anyone interested in a PhD in theoretical physics, as this is material usually taught to beginning graduate students.

Restrictions: typically offered only to Y2 and above.

Higgs couplings fits

Faculty advisor: Veronica Sanz

The student will learn the basic concepts of the Higgs mechanism and use data coming from the Large Hadron Colllider to produce a fit of the Higgs couplings. The fit will be done in Mathematica, and then used to constrain new physics, such as Supersymmetry

Warped extra-dimensional models

Faculty advisor: Veronica Sanz

In this project the student will learn about theories with new dimensions of space-time, and implement in Feynrules (a Mathematica package) the interactions of a very attractive model for the Large Hadron Collider, the bulk Randall-Sundrum model.

Jet physics at the LHC

Faculty advisor: Andrea Banfi

Jets, highly collimated bunches of energetic hadrons, are ubiquitous in today's particle physics. This is because the LHC, the machine with which we wish to discover physics beyond the Standard Model, is in fact a hadron collider. The project deals with the calculation of an observable involving jets, relevant either for precision studies or new physics searches at the LHC.

Brief introduction to Quantum Chromo-Dynamics (QCD), the theory underlying jet physics, analytic modelling of the observable, numerical analysis, programming in various languages (Python, C++, Fortran).

Newton's potential in gravitational theories beyond General Relativiy

Faculty advisor: Xavier Calmet

You will learn about General Relativity (GR) and how to extract Newton's 1/r potential from the metric. After reviewing standard GR calculations and in particular the leading order GR correction to the 1/r potential, you will consider modifications of GR and study how these modify Newton's potential.

Furthermore, during this project you will learn about differential equations and how to solve them using Maple or Mathematica.

Phase transitions in statistical and particle physics

Faculty advisor: Daniel Litim

Phase transitions play a central role in many physical systems including fundamental particle physics, early universe physics, or solid state physics. You will study phase transitions in a simple system, both analytically and numerically, by using the modern methods of the renormalization group. Some part of the project may require the use of numerical tools such as Maple, Mathematica or Matlab, also to allow for a good visualisation of results.

Phase transitions in the early universe

Faculty advisor: Stephan Huber

Is the cosmic matter-antimatter asymmetry related to a phase transition in the early universe? To answer this question we must understand the dynamics of cosmic phase transitions.

You will learn how to describe phase transitions in the context of field theory and how to compute their basic properties. The aim is to test if a given model of non-standard particle physics can explain the matter-antimatter asymmetry. (This is a project at the interface of particle physics and cosmology.)

Restrictions: Theorists have some advantage, but non-theorists are not explicitly ruled out.

Quantum systems from confined cold atoms

Faculty advisor: Barry Garraway

Quantum physics offers exciting routes to new devices such as high precision interferometers, motion sensors, realistic designs for large-scale quantum simulations, and quantum logic modules leading to quantum information processors. This project involves theoretical studies of new ways to confine very small numbers of atoms to realise these kinds of devices. You will start with understanding the literature and with simulations of classical models of atom-chip and related systems which confine the atoms using electromagnetic fields. We will also undertake a quantum analysis and new designs will be made for structures that trap atoms about micro-fabricated surfaces.

In this project you will be involved in computer simulations, visualisation and with theoretical models.

Solitons and oscillons

Faculty advisor: Mark Hindmarsh

Field theory underpins fundamental physics: particles are just quantised wave oscillations in non-linear field theories. Inthe very early Universe, the classical behaviour of the same field theories becomes important, describing the progress of phase transitions in the early universe, and manifesting itself in the form of extended stable and metastable structures called solitons and oscillons.

Examples of solitons are magnetic monopoles and cosmic strings, which are known to exist and be stable in many theories thought to descibe physics at very high energies. Oscillons are perhaps even more mysterious: they are oscillating lumps of energy which appear to be stable in 2 dimensions, but for reasons which are not understood. No stable oscillons have been found in 3 dimensions.

In this project, you will start by learning about non-linear partial differential equations, which are used to describe field theory in the classical limit. You will then learn the numerical techniques required to solve them. You can write your own, or adapt some code written in C++ if you are interested in parallel programming. You will learn how to visualise the output in Python or Matlab and make movies of your simulations. Using these techniques there are several possible projects. You can study 3-dimensional oscillons and simulate their formation in the very early Universe; study cosmic strings in supersymmetric extensions of the Standard Model; or examine the propagation of phase boundaries in cosmological phase transitions.

Activities are mainly theory and computing.

Symmetry breaking in particle physics

Faculty advisor: Sebastian Jaeger

Symmetry is the central theoretical concept in contemporary particle physics: the gauge symmetry principle gives rise to the forces between elementary particles, while a number of approximate and exact global symmetries underly approximate conservation laws of baryon and lepton number, flavour, parity (mirror) and matter-antimatter (CP) symmetry. Finding the correct theory of how gauge and global symmetries are broken in fundamental physics is a major open problem, which has sparked bold ideas such as supersymmetry and extra spacetime dimensions. The new experiments at the LHC are starting to provide data which should shed light on this question.

In this project you will study theoretical mechanisms of symmetry breaking and make contact with emerging new experimental results, toward the overarching goal of identifying the correct theory to replace the Standard Model.

Depending on your interests, this may centre around the more theoretical-conceptual aspects or take a more phenomenological, data-driven approach. Skills to be developed include: analytical thinking and maths, physical modelling of complex situations, quantitative predictions including error estimates, all of which are central to physics research but universally applicable.

Lorentz, canonical and gauge transformations in moving media

Faculty advisor: Claudia Eberlein

The project investigates Lorentz transformations of electromagnetic fields in a moving dielectric or conducting medium and under which circumstances these could be counteracted by a gauge transformation in the fields and a canonical transformation in the Hamiltonian. This is important for the description of quantum friction in nano devices.

This is a theoretical project techniques of mathematical anaysis.

Listen to Nathaniel Wiesendanger Shaw, MPhys Theoretical Physics (Research Placement) student talking about his summer 2014 Research Placement