Possible MPhil/PhD Projects in Physics

Quantum information processing (QIP) is information processing that harnesses the power of quantum mechanics. Often referred to as the “Second Quantum Revolution”, quantum computing promises exponentially superior computing power compared to today’s classical computers and quantum cryptography promises cryptography that is perfectly secure, by exploiting the uniquely quantum effects of superposition and entanglement – an effect famously described by Albert Einstein as “spooky action at a distance”. While enormous experimental and practical challenges need to be overcome before QIP is widely used, the global scientific community remains excited about the immense potential impact that QIP will have on all aspects of society. In fact, when the 2012 Nobel Prize in Physics was awarded to Serge Haroche and David J. Wineland, the Nobel Committee predicted that “the quantum computer will change our everyday lives in this century in the same radical way as the classical computer did in the last century”.

The Quantum Photonics Group at Newcastle University performs experimental research at the interface of solid-state quantum optics and nanophotonics, for applications in quantum computing, quantum communication and cryptography, and other emerging quantum technologies. Specifically, our group investigates the optical properties of single-photon emitters and spin qubits in III-V epitaxial quantum dots (QDs), 2D materials, and diamond, as well as their optical coupling to nanophotonic and nanoplasmonic devices.

We invite applications from outstanding and highly motivated students to undertake a PhD project that will investigate single-photon emitters and spin qubits in III-V epitaxial QDs, 2D materials, and/or diamond, as well as explore their optical coupling to nanophotonic devices, for applications in QIP and other quantum technologies.

Laboratory work will include high-resolution optical spectroscopy, nanoscale device fabrication, state-of-the-art electron microscopy, and theoretical device modelling; therefore, previous experience using these techniques will be an asset. The successful applicant will be joining a world-class school and university, have access to state-of-the-art research facilities including those at nanoLAB and NEXUS, and have the opportunity to engage with world-leading academics and scientists, including those at the Joint Quantum Centre. Further, the successful applicant will have the opportunity to work closely with collaborators at other top research institutions in the UK and internationally, including those at Cambridge University and the National Institute for Materials Science (Japan).

Potential applicants are strongly encouraged to contact Dr Jonathan Mar for further information and informal discussions.

Supervisor: Dr Jonathan Mar

The mastery of the photon and its application has become one of the most important innovation drivers for modern society and its economy.

Successful candidates will pursue a research programme in one of the fields of:

• quantum optics
• nonlinear photonics
• material’s science
• fundamental physics

The work will be undertaken in a world-class photonics laboratory with facilities and lasers that are at the cutting edge of research.

Supervisor: Prof Noel Healy

The implication of climate changes on the environment and on people’s well-being has resulted in a growing need for energy production through renewable resources. Solar has been traditionally one of the most intensively pursued. However, current solar technologies will not be able to meet the increasing demand and new materials must be designed. Likewise, energy storage systems will have to be further developed, to offset the intermittency in energy production through renewable sources and to make it available to end-use applications, such as electric vehicles.

In our laboratory we pursue the development of new and existing materials which will constitute the building block of next generation solar technologies and energy storage devices. Current research themes include:

• Design and synthesis of mixed anions materials for solar applications
• Fabrication and characterisation of photovoltaic devices based on emerging solar absorbers
• Development of in-operando X-ray Photoelectron Spectroscopy techniques to characterise solar devices under operating conditions
• Development of in-operando X-ray Photoelectron Spectroscopy techniques for the characterisation of battery materials.

Supervisor: Dr Elisabetta Arca

Graphene is just one of a whole class of 2D materials characterised by being only one atom thick.

One property of 2D materials is that they are literally all surface! This makes them ideally suited to us as sensors elements:

• gas sensors
• strain sensors
• electrochemical sensors

We are interested in sensor applications for 2D materials. From research into the mechanism of transduction all the way to solving real-world problems such as infrastructure monitoring and health.

Supervisor: Dr Toby Hallam

We have shown recently that the structure and geometry of nanostructured contacts can enhance electrical conductivity of metal semiconductor junctions compared to standard contacts (see paper with Digital Object Identifier: 10.1021/acsami.7b06595).

In this project you will characterise the electrical and physical characteristics of these nanostructured contacts using electron microscope and image analysis. This will enable several applications in low temperature electronics, device technology and energy conversion.

Supervisor: Professor Anthony O'Neill

The government undertakes little monitoring of the North Sea even though there are many mammals (dolphins, whales etc) and other animals who might be affected by plastic pollution and run-off from farm fertilisers.

Activists and agencies lack sufficient resources as current monitoring technology is very expensive.

This project will investigate the possibility of using digital prototyping (eg specialist 3D printing materials to modify commercial electronics) for use as low-cost environmental sensors via field trials in collaboration with local partners.

Supervisor: Prof Nick Wright

Reliable theoretical prediction of the properties of materials is of huge importance in the modern world.

Our group employs sophisticated methods and algorithms to model materials based on the fundamental equations of quantum mechanics. We aim to predict such properties without empirical input.

This is a rapidly changing and exciting field of research. This is due to given continually improving methods and ever more powerful supercomputers. Furthermore, skills obtained in numerical analysis and computational physics are highly transferable.

Projects are available in both methodological development and the application of methods.

Supervisor: Dr Mark Rayson and Dr Jon Goss

Metamaterials (artificial electromagnetic media) and metasurfaces (their 2D version) can provide full control of light-matter interactions by arbitrarily tailoring the electromagnetic response of matter.

They can be applied at different frequency ranges such as: acoustics, microwaves, Terahertz and optics.

They offer great opportunities in applications such as:

• Levitation and invisibility cloaking.
• Plasmonic nano structures
• Quasi-optical devices
• Spatiotemporal modulation of fields and waves.

Our group is focused on the theoretical, numerical, and experimental study of metamaterials and metasurfaces from their basic principles and their applications to spatial, temporal and spatiotemporal manipulation of wave propagation.

Supervisor: Dr Victor Pacheco Pena

Although relatively immature, Gallium Nitride is considered a disruptive technology and already finds applications in communications, electric cars and power generation. If we could replace Silicon with Gallium Nitride we could make a saving of £1 Trillion a year in global energy costs alone.

In order to realise these energy savings a number of challenges must be overcome. Our group employs a mix of analytical theory and high-performance computer simulation to study the profound changes that occur on the nanoscale in Gallium Nitride aggressively scaled devices.

Projects are available in:

• Monte-Carlo simulation both development and application
• theory of confined electrons and phonons in nanostructures

Supervisor: Dr Angela Dyson

Since the advent of graphene in 2004, the research of two-dimensional (2D) materials has been growing at an unprecedented rate. They are one atom thick. The family of such materials includes graphene, transition metal dichalcogenides and trichalcogenides, hexagonal boron nitride, phosphorene, silicene, germanene, 2D oxides and many others.

They cover a wide range of properties and offer an opportunity to create artificial materials by stacking them on top of each other in a Lego style, layer-by-layer in a chosen sequence. The properties of resultant structures, so-called van der Waals heterostructures, can be tailored to specific applications depending on their constituent materials. Examples of such structures include field effect transistors, tunnelling transistors, light emitting diodes, lasers, etc. Given the large amount of available 2D materials, the number of their combinations can be huge. Moreover, relative orientation of layers weakly held by van der Waals forces in a heterostructure can drastically modify its properties. As a result, there are many possibilities to search for and study exotic or new physical phenomena.

 The main focus will be on experimental investigation of optoelectronic properties of light emitting heterostructures. Current topics include

• Quantum light sources in 2D materials
• Interlayer excitons in 2D heterostructures
• Strain- and defect- bandgap engineering in 2D materials and their alloys

The applicant will gain a variety of skills in nanofabrication, optical and electron transport measurements, scanning probe microscopy and instrumentation development. The applicant will have access the world-class measurements facilities and cleanrooms at Newcastle University.

Supervisor: Dr Aleksey Kozikov

Two-dimensional (2D) materials, such as the Nobel Prize in Physics awarded graphene, are one of the most active research topics in physics, materials science and engineering due to their prominent mechanical, electrical, optical and spintronics properties. At Newcastle, we are interested in exploitation of different quantum degrees of freedom (spin, pseudospin and valley) in lithographically patterned heterostructure devices based on novel 2D materials for applications in energy-efficient information technologies. Below, you will find available project topics together with our relevant publications:

• Novel electronic devices based on 2D materials (Nature 587, 72-77 (2020), Nature 560, 340 (2018))
• 2D (topological) magnets (Nature Nano., 14, 674-678 (2019), Nature Comm., 11, 1-7 (2020))
• Electronic spin transport and proximity physics in 2D materials (Nature Phys., 13, 888-894 (2017), Rev. Mod. Phys., 92 (2), 021003 (2020))
• Spin-based logic circuits

You can find out more information on our group website.

Supervisor: Dr Ahmet Avsar

The complex magnetic structures (coronal loops and prominences) that appear on the Sun's surface are believed to originate at the bottom of the solar convection zone. This is where the magnetic field is stretched and amplified until it becomes buoyant and rises to the surface. However, the details of this magnetic buoyancy process are poorly understood and are strongly affected by the Sun's rotation and compressibility.

This project will combine analytical theory with high-resolution numerical simulations, to determine how magnetic buoyancy operates under the conditions of the solar interior. We will also address the role that the rising magnetic field structures play in the Sun's overall dynamo process.

We will assume no prior knowledge of solar physics. A good understanding of fluid dynamics is essential.

Supervisors: Dr Toby Wood and Dr Paul Bushby

The evolution of stars and their ultimate demise is affected by hydrodynamic processes occurring within their interiors throughout their lifetime.

Dynamical processes such as convection, rotation, waves and magnetism all greatly impact how these stars explode, chemically enrich the galactic environment and the properties of the stellar remnant.

This project will involve using multi-dimensional hydrodynamic processes to understand these dynamical processes and how they contribute to stellar evolution. Using this understanding, combined with observational constraints, we will develop one-dimensional prescriptions for use in standard stellar evolution models.

Supervisor: Prof Tamara Rogers

Neutron stars are extremely dense and rapidly rotating objects. They have the strongest magnetic fields in the Universe. Regular stars are powered by nuclear reactions. Neutron stars are powered by their vast reservoirs of rotational and magnetic energy.

A neutron star has a solid outer crust surrounding a superfluid core. Within this core the rotation and magnetic field are "quantised" into thin filaments called vortices and fluxtubes.

This project will develop a model for the dynamics of the vortices in the star's core, and their interaction with the strong magnetic field. We will base our model on suitably modified fluid equations that take account of the superfluid nature of the core.

Basic knowledge of fluid dynamics is required, as well as interest in developing computational skills.

Supervisors: Dr Toby Wood and Prof Carlo F Barenghi

Weak gravitational lensing is now established as one of the most compelling probes of cosmology, allowing to map out the dark matter distribution on the sky while providing some of the best measurements of its clumpiness and abundance. Existing cosmic shear data such as that from the Kilo Degree Survey (KiDS) are currently being analysed and novel methods are being deployed in order to maximize their scientific outcome.

Among these, simulation-based approaches are receiving an increasing level of attention for their potential at better capturing the information contained in the data. In this project, the PhD student will specialize in some of these novel analysis techniques, validate the methods on simulations at first, then apply the findings on the KiDS legacy data, and subsequently on the first data release of the LSST and Euclid surveys.

Supervisor: Dr Joachim Harnois-Deraps

The 21st century has transformed cosmology from a speculative field into a precision science driven by theoretical methods, numerical simulations and galaxy survey data. Measurements of galaxy clustering and weak gravitational lensing will map the 3d matter distribution over the past 10 billion years and answer fundamental questions in physics: What are the properties of the early universe? What is the nature of dark energy? What are the characteristics of dark matter?

A slice through the Euclid Flagship mock catalog of 2.6 billion galaxies displaying the growth of structure over 10 billion years from early (green/right) to late times (red/left).

Unravelling these mysteries is difficult because the information is hidden in the galaxy distribution that has been shaped by nonlinear clustering and is characterised by complex non-Gaussian statistics. As a PhD student working on this project, you will develop and apply state-of-the art statistical, analytical and computational techniques to extract the maximal information on fundamental physics from the late-time matter distribution. You will be part of a local research team in Newcastle and have the option to join the Euclid Consortium to contribute to the ESA space mission Euclid which will launch a dedicated satellite in 2022 to map the dark universe across one third of the sky.

Supervisor: Dr Cora Uhlemann

Cosmology is enjoying an era of unprecedented data abundance, with powerful observations already available and next-generation surveys on the immediate horizon. This wealth of data provides an exciting opportunity to pin down the nature of the mysterious dark energy which makes up 70% of the Universe. This PhD project will develop crucial, cutting-edge techniques for the analysis of modern cosmological survey data, and will apply these and other techniques to existing data in order to achieve new insight into the composition, history, and physical laws of our Universe.

Supervisor: Dr Danielle Leonard

Our understanding of dark matter remains elusive despite recent successes. A revolutionary recent idea suggests that dark matter could actually exist in the form of a gigantic cosmic superfluid, whose wave phenomena span thousands of light-years. Such studies, still at their infancy, have so far only been conducted in a simple non-interacting condensate picture of scalar dark matter.

The aim of this ambitious, interdisciplinary project (supervised by both cosmologists and cold-atom theorists) is to utilise stochastic techniques established in ultracold atomic physics – where they offer precise quantitative agreement with controlled experiments – to understand such cosmic superfluids. We aim to go beyond simple models used to date and include, for example, effects of self-interactions, while also allowing the co-existence of dark matter particles in both a condensed and a gas-like, non-condensed component, separated by a phase transition.

The goal of this ambitious project is to understand Bose-Einstein condensation on cosmological scales, and notably in a setting where the phase transition is actually driven by self-collapse due to gravity. Our numerical simulations will map the relevant parameter space, and could eventually lead to placing constraints, in combination with astrophysical observations.

Supervisors: Dr Gerasimos Rigopoulos and Professor Nick Proukakis

The main goal of our cosmology programme is to search for direct observational signatures of early universe cosmological models, paying special attention to the role of quantum processes during a period of cosmological inflation. This PhD project covers topical aspects of the very early universe, including:

• the quantum theory of the big bang and the origin of time
• investigations of inflationary models with quantum gravity and Higgs bosons
• models which seek to explain the origin of primordial magnetic fields

Supervisor: Prof Ian Moss

Observational cosmology has undergone a revolution in recent years due to the availability of high-quality data from satellite observations. This makes it possible to attempt to find out what makes up the dominant form of matter in the universe. It also helps us understand the mysterious dark energy which is driving the universe apart. This PhD project attempts to fit models of dark matter and dark energy to observations of large scale structure using new approaches and new theories of dark energy.

Supervisor: Prof Ian Moss

The cosmic large-scale structure is the skeleton of matter on the largest scales in the Universe. Galaxies trace this large-scale skeleton of dark matter and form in large gravitationally bound dark matter structures. With major upcoming galaxy surveys like Euclid and LSST, we will be able to track the growth of structure through time across large volumes. This will provide a cosmic laboratory for testing cosmology, fundamental physics and astrophysics with the large-scale structure. To extract the maximum amount of information from galaxy surveys, we need a) accurate models for the gravitational dynamics of the dominant dark matter component, and b) powerful statistics that capture key aspects of gravitational clustering.

This PhD project will tackle these two intertwined challenges. First, we will use novel techniques to describe gravitational dark matter dynamics, for example using the quantum-classical correspondence. The goal is to develop new analytical and computational tools to solve for the time-evolution of dark matter and hunt for signatures of particular dark matter candidates. Second, we will develop clustering statistics that capture non-Gaussian properties of the late-time matter distribution. The idea is to use a sweet spot of simple statistics that are easy to measure, and can be accurately predicted into the nonlinear regime. With this, we will seek to improve the standard analysis relying on two-point statistics to obtain unique insights into cosmology, fundamental physics and astrophysics.

Supervisor: Dr Cora Uhlemann

Neutron stars are extremely dense cinders remaining after stellar explosions. They often have strong magnetic fields and rotate rapidly, and this combination often results in their appearing to pulsate with extreme regularity. We call these objects "pulsars", and their measurable rotation provides an opportunity to take precision measurements in some of the most extreme astrophysical environments accessible to observation.

This project will use existing observations and request and carry out new observations of pulsar systems. These observations will strongly constrain theoretical models of how matter falls onto neutron stars, and in fact probe the details of how gravity works - does it behave as Einstein predicted?

An understanding of the basics of astronomical observation and data analysis is required, as is an interest in understanding models of these phenomena and how to test them.

Supervisor: Dr Anne Archibald

Landmark experiments with atomic quantum gases since 2017 have demonstrated a new form of quantum matter - a quantum droplet. These droplets have several unusual properties:

• they are superfluid - meaning that they are free from viscosity and can support eternal flow
• they are self-supporting - like stars under their own gravity
• they also have such high particle density that quantum mechanical fluctuations and correlations, normally negligible in the gas phase, become significant

These unique features bring the droplets to the fore for studying exotic physics, such as laboratory analogs of neutron stars and highly-correlated quantum systems, and developing new technologies, such as ultra-precise sensors.

This timely project will develop computational and/or analytical models of the droplets to explore these state-of-the-art opportunities.

Supervisors: Dr Nick Parker and Dr Tom Billam

Cooling a gas of magnetic atoms down to absolute zero creates a so-called quantum ferrofluid, which combines two of the most extraordinary types of fluid - the quantum fluid and the ferrofluid.

Quantum fluids are fluids in which quantum mechanics takes over. They have no viscosity, can flow forever, and are well-known in the context of superfluid Helium and atomic Bose-Einstein condensates.

Meanwhile, ferrofluids are fluids of magnetic particles which can be controlled and directed by magnetic fields (indeed, they were first created by NASA as a rocket fuel to use in zero-gravity environments), give rise to fascinating patterns (try googling “ferrofluids”) and have found major technological applications.

What strange behaviours emerge when ferrofluids go quantum?
How can we control them using magnetic fields?
And what can they tell us about the fundamentals of magnetism and quantum physics?

These questions and more will be explored with state-of-the-art computational and/or analytic approaches.

Supervisors: Dr Nick Parker and Dr Andrew Baggaley

Imagine circuitry with neutral atomic carriers, instead of electrons and holes. The most evident features that result from such a design would be a reduced decoherence rate due to charge neutrality of the atomic currents, an ability to realise quantum devices with fermionic or bosonic carriers, and a tuneable carrier–carrier interaction from weak-to-strong, from short-to-long range, from attractive-to-repulsive in type. The rapid progress in ultracold atoms and device miniaturisation is spurring this dream to reality.

The newly-emerging field of atomtronics refers to harnessing ultracold atomic matter to produce devices that offer novel opportunities for precision measurements, including rotational sensing. The first prototype atomtronic circuit was experimentally demonstrated in 2014 and the field has rapidly taken off since then. The name atomtronics has been coined by analogy to electronics. It refers to circuits in which ultracold atoms are used to create atomic analogues of electronic components, such as transistors and diodes. Closed atomic circuits are facilitated by doughnut-shaped traps for the atoms, while the atomic dynamics are controlled by moving laser beams that allow for minimal matter transfer across a so-called `Josephson junction’, which acts as a weak link between different parts of the quantum fluid.

This project aims to study a range of such currently experimentally-accessible atomtronic devices using in-house state-of-the-art numerical simulations, with findings directly applied to experimental measurements and prototype circuits. Intended outputs include a detailed understanding of an atomtronic quantum interference device, or precision rotation sensor, a rudimentary demonstration of which has already been performed at the Los Alamos Laboratory in the U.S.

Supervisor: Prof Nick Proukakis

We know well what happens when two classical systems interact: they can mix (eg milk and water), or phase-separate (eg oil and water). What happens then when two quantum fluids overlap? This depends crucially on their interaction strength, with the quantum nature of the many-body system setting new rules for their coupling – critically also depending on whether the atomic system is composed of bosonic, or fermionic, particles.

Motivated by experiments with a plethora of different mixtures of ultracold quantum gases, at temperatures below micro-Kelvin, the aim of this project is to study the static and dynamic properties of such multi-component systems.

Questions to be studied include:

• How do such quantum mixtures emerge from their classical systems across the phase transition?
• What difference does the bosonic, or fermionic, nature of the individual components play, and how does a double superfluid (ie a fluid in which both bosonic and fermionic components of a Bose-Fermi mixture are superfluid) differ from other mixtures?
• In particular, how does rotation influence the dynamics of quantum mixtures? (a question of indirect relevance to the cores of neutron stars)
• How does the presence of external (electromagnetic) coupling between different components influence the system’s properties?

Such questions will be addressed in close collaboration with European experimental groups, where such experiments are underway.

Supervisors: Professor Nick Proukakis and Professor Carlo Barenghi

Experimental advances over the last decade are beginning to usher in an age of quantum devices, such as sensors and interferometers. They have the potential to surpass their classical predecessors in terms of:

• sensitivity
• reliability
• miniaturization

One paradigm for constructing such devices involves using ultracold atoms as the quantum element. This has led to the creation of "atomtronic" analogs of electronic (and optical) devices in which the electrons (or light) are replaced with a superfluid current of ultracold atoms. This atomic superfluid can be made to flow without viscosity through carefully shaped channels in a similar way to electricity flowing through circuits, and light travelling through photonic media such as optical fibres or nonlinear crystals. Owing to many-body quantum effects inherent in the atomic superfluid, atomtronics has possible applications in making ultra-sensitive, quantum-enhanced sensors and interferometers.

This project will develop computational and analytical models of novel atomtronic quantum interference devices. In particular, we will connect with recent developments in quantum electronics to generate and develop new proposals for atomtronic devices that exhibit quantum-enhanced performance.

Supervisors: Dr Tom Billam and Dr Clive Emary

Our understanding of dark matter remains elusive despite recent successes. A revolutionary recent idea suggests that dark matter could actually exist in the form of a gigantic cosmic superfluid, whose wave phenomena span thousands of light years. Such studies, still at their infancy, have so far only been conducted in a simple non-interacting condensate picture of scalar dark matter.

The aim of this ambitious, interdisciplinary project (supervised by both cosmologists and cold-atom theorists) is to utilise stochastic techniques established in ultracold atomic physics – where they offer precise quantitative agreement with controlled experiments – to understand such cosmic superfluids. We aim to go beyond simple models used to date and include, for example, effects of self-interactions, while also allowing the co-existence of dark matter particles in both a condensed and a gas-like, non-condensed component, separated by a phase transition.

The goal of this ambitious project is to understand Bose-Einstein condensation on cosmological scales, and notably in a setting where the phase transition is actually driven by self-collapse due to gravity. Our numerical simulations will map the relevant parameter space, and could eventually lead to placing constraints, in combination with astrophysical observations.

Supervisors: Dr Gerasimos Rigopoulos and Professor Nick Proukakis

Mathematicians, physicists and engineers have studied turbulence for more than a century. Almost all investigations into this fundamental problem of the natural sciences have concentrated the attention on two aspects:

• the geometry
• the dynamics of turbulence

Little attention has been paid, in comparison, to a third equally important aspect: the topology.

This is despite the fact that 19th-century pioneers of fluid dynamics such as Kelvin and Helmholtz were already aware of the possibility of vortices becoming twisted, linked and knotted. Unfortunately, until recently, the only vortex structures which could be created in the laboratory were either very simple (such as vortex rings) or utterly complex (such as turbulence): the 'hydrogen atom' of topological complexity was missing. This situation suddenly changed in 2013, when Kleckner and Irvine, at the University of Chicago, showed that it is possible to create trefoil vortex knots under controlled and reproducible laboratory conditions. This breakthrough is now driving a great interest in the study of the topology of vortices and turbulence.

The project aims to:

• perform a numerical investigation of turbulent flows by solving the governing Euler or Navier-Stokes equations
• look for evidence of knotted structures

The objectives are to:

• define and quantify the topological complexity of turbulence
• to explore the possibility of scaling laws

You should have an interest in fluid dynamics and methods of computational mathematics. You should be willing to learn tools from other relevant disciplines such as knot theory.

Supervisors: Professor Carlo F Barenghi and Dr Andrew Baggaley

Recent experiments at Edmonton (Canada) and Grenoble (France) have shown that it has become possible to detect accurately the motion of superfluid helium in micron-sized cavities (1) or using micron-sized cantilever probes (2). These experimental techniques have opened up new exciting problems of fluid dynamics, such as the controlled transition from three-dimensional to two-dimensional turbulence (which, defying entropy expectations, can develop large scale order), or controlled measurements of the tension and the reconnections of quantised vortex lines. At the same time, it has become possible to realistically numerically simulate the motion of quantised vortex lines near boundaries which are necessarily rough at the atomic scale of the vortex core (3,4).

The aim of this project is to tackle the two problems mentioned above by solving numerically the governing Gross-Pitaevskii equation, making direct connection with the experiments and revealing the nature of the motion of superfluids at the quantum scales.

(1) E Varga et al, Physical Review Letters, 125, 025301 (2020)

(2) J Salort et al, Review of Scientific Instruments, 83, 125002 (2012)

(3) G Stagg et al, Physical Review Letters, 118, 135301 (2017)

(4) N Keepfer et al, Physical Review B, 102, 144520 (2020)

Supervisor: Prof Carlo F Barenghi

Black holes represent the most catastrophic end point of stellar evolution and posses the most extreme grativational field possible. The vast majority of black holes are invisible to us. However, we can detect those that are accreting material, since the accretion disc that forms around the black hole becomes hot enough to glow brightly in X-rays. This reveals two populations of black holes: X-ray binaries – whereby a stellar-mass black hole accretes from a stellar companion – and active galactic nuclei – whereby a supermassive black hole accretes from its host galaxy. However, the vicinity of the black hole is far too small to directly image, and so indirect mapping techniques are required if we are to observe how matter behaves just before it falls forever beyond the event horizon.

Until now, we have only been able to measure the brightness of the X-rays and how this depends on wavelength and time. This will change in December 2021 when NASA's Imaging X-ray Polarimetry Explorer (IXPE) launches. IXPE will be the first satellite for more than 40 years capable of measuring the polarisation of X-rays. Since its sensitivity is more than 100 times that of its predecessors, it will be able to make the first firm detections of polarisation for X-ray binaries and active galactic nuclei.

The successful candidate for this PhD project will become an associate member of the IXPE team in order to analyse and develop models for new IXPE data from X-ray binaries and active galactic nuclei. In particular, we will analyse how the polarization degree and angle depends on X-ray wavelength and we will apply state-of-the-art techniques to test whether or not the polarization angle is swinging back and forth with time; which is predicted to happen if the inner accretion flow is being caused to wobble around the black hole spin axis by a relativistic effect called frame dragging. We have theoretical expectations, but we do not really know what the polarization of these objects will be until the data start to come down from IXPE. The successful candidate will be at the forefront of this journey of discovery, looking at black holes through the entirely new window of X-ray polarization.

Supervisor: Dr Adam Ingram

Weak gravitational lensing is now established as one of the most compelling probes of cosmology, allowing to map out the dark matter distribution on the sky while providing some of the best measurements of its clumpiness and abundance. Existing cosmic shear data such as that from the Kilo Degree Survey (KiDS) are currently being analysed and novel methods are being deployed in order to maximize their scientific outcome.

Among these, simulation-based approaches are receiving an increasing level of attention for their potential at better capturing the information contained in the data. In this project, the PhD student will specialize in some of these novel analysis techniques, validate the methods on simulations at first, then apply the findings on the KiDS legacy data, and subsequently on the first data release of the LSST and Euclid surveys.

Supervisor: Dr Joachim Harnois-Deraps

The James Webb Space Telescope (JWST) is the most anticipated space observatory of this generation. With unprecedented capabilities for infra-red astronomy, it will revolutionise our studies of galaxies and supermassive black holes. In this project, you will work with some of the first data that will be taken with JWST to explore the central regions of nearby active galactic nuclei (AGNs), galaxies in which supermassive black holes are growing. Collaborating with the

Galaxy Activity, Torus and Outflow Survey (GATOS), you will use a wide range of multiwavelength observational datasets to uncover dusty winds emanating from these AGNs, and quantitatively constrain their mass and energy outflow rates. You will bring together information from JWST images and spectroscopy to understand the interplay between the AGN and star-formation in these galaxy centres.

As a motivated student taking on this project, you will be expected to work with a large international team on some of the most cutting-edge observations available. A strong background in data analysis and programming will be beneficial, particularly Python in order to use available JWST analysis tools and develop new ones. Familiarity in the topics of AGN science and infra-red astronomy is beneficial, but not required.

JWST programme summary

GATOS

Our research group

Supervisor: Dr David Rosario

The James Webb Space Telescope (JWST) is the most anticipated space observatory of this generation. With unprecedented capabilities for infra-red astronomy, it will revolutionise our studies of galaxies and supermassive black holes. In its first year of operation, JWST will spend a considerable amount of time surveying small areas of the sky to incredible depths, capturing thousands of galaxies out into the distance Universe. By combining these new surveys with existing data across a wide range of wavelengths (X-rays to the radio bands), you will use modern analysis techniques to find a robust set of rapidly-growing supermassive black holes (also called Quasars) in the distant Universe. You will then employ the game-changing capabilities of the JWST data to understand the nature of the galaxies that host these Quasars, and compare them to other galaxies at the same era in which the black holes are not growing.

These studies will reveal if the important processes that transform and evolve galaxies are connected to the growth of supermassive black holes.

Our research group

Supervisor: Dr David Rosario

Cosmology is enjoying an era of unprecedented data abundance, with powerful observations already available and next-generation surveys on the immediate horizon. This wealth of data provides an exciting opportunity to pin down the nature of the mysterious dark energy which makes up 70% of the Universe. This PhD project will develop crucial, cutting-edge techniques for the analysis of modern cosmological survey data, and will apply these and other techniques to existing data in order to achieve new insight into the composition, history, and physical laws of our Universe.

Supervisor: Dr Danielle Leonard

Neutron stars are extremely dense cinders remaining after stellar explosions. They often have strong magnetic fields and rotate rapidly, and this combination often results in their appearing to pulsate with extreme regularity. We call these objects "pulsars", and their measurable rotation provides an opportunity to take precision measurements in some of the most extreme astrophysical environments accessible to observation.

This project will use existing observations and request and carry out new observations of pulsar systems. These observations will strongly constrain theoretical models of how matter falls onto neutron stars, and in fact probe the details of how gravity works - does it behave as Einstein predicted?

An understanding of the basics of astronomical observation and data analysis is required, as is an interest in understanding models of these phenomena and how to test them.

Supervisor: Dr Anne Archibald