Lady Bertha Jeffreys PhD Studentship
Available PhD projects
Click on each topic to learn more with links to supervisors' contact details
Quantum matter
– Ultracold Quantum Sensors & Atomtronics
– Measurement-based thermodynamic devices
Cosmology and Observational Astronomy
– X-ray polarization: a new window to understand black holes
– The cosmic web as a laboratory for fundamental physics
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Ultracold Quantum Sensors & Atomtronics
Quantum technologies with ultracold atoms is an exciting area of intense experimental and theoretical research. One of the promising avenues in this direction is the use of (neutral) ultracold atomic gases in closed circuits in what has become known as the emerging field of atomtronics [1], a key strength of which derives from the experimental flexibility of potential landscapes, which allows for new quantum device architectures and functionalities which have no analog in conventional electronics. Within this broader context, which facilitates a variety of different research avenues, the specific aim of this PhD project is to devise and numerically simulate strategies for ultracold quantum sensors – similar to the recently-observed atomic analogue of the superconducting quantum interference device [2] – utilizing atom neutrality and sensitivity to external fields to produce next-generation rotation and acceleration sensors. This project focusses on numerically modelling ultracold atom dynamics across single and multiple connected closed (ring-trap like) geometries, with particular attention paid on quantum transport across Josephson junctions, stability and transport of persistent currents, and interaction across coupled superfluids, by means of advanced stochastic and kinetic models [3] which fully account for the interaction of the superfluid gas with the co-existent incoherent thermal cloud. As such, the successful student will gain experience across diverse thematic areas, including non-equilibrium quantum modelling under realistic experimental conditions; ultracold quantum sensors; dynamics of persistent currents; superflow transport across Josephson junctions and coupling across different superfluid components, while simultaneously learning high-end numerical computing and being exposed to collaborations with leading experimental groups in the UK and beyond.
[1] L. Amico et al., Roadmap on Atomtronics: State of the art and perspective, AVS Quantum Sci. 3, 039201 (2021) ( https://doi.org/10.1116/5.0026178 )
[2] C. Ryu et al., Quantum interference of currents in an atomtronic SQUID, Nat. Communications 11, 3338 (2020) ( https://doi.org/10.1038/s41467-020-17185-6 )
[3] N. Proukakis et al., Finite Temperature and Non-Equilibrium Dynamics, World Scientific (2013) ( https://doi.org/10.1142/p817 )
Supervisor: Prof Nick Proukakis
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Measurement-based thermodynamic devices
The measurement and quantification of the entanglement in a many-particle system is currently a central topic at the intersection of quantum information theory and condensed matter physics. In the past decade, the topic of information in thermodynamics has gained recent prominence. The second law of thermodynamics taking explicit account of information acquired from measurement and manipulation of small, fluctuating systems have been generalised and experimentally verified in various platforms.
In addition, recent studies have introduced a single-particle quantum machines entirely powered by a position-resolving measurement. The peculiarity of this proposed machines is exploiting the measurement back-action as a “fuel” under a favourable condition. Although, it is not yet clear how to scale up such machines to systems composed of many quantum particles. However, understanding the exact roles of entanglement, energy fluctuations and finite-time dynamics of this machine is important for its technological applications.
In this project, we will develop a theoretical framework of a quantum information thermodynamic machines in general nonequilibrium setting.
Supervisor: Dr Obinna Abah
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The prediction by Stephen Hawking that black holes radiate particles from the quantum vacuum has had a profound impact on the development of quantum gravity. One aspect of this has been the realisation that quantum gravity theories have non-gravitational equivalents in one less dimension-the holographic principle. This PhD project is concerned with theoretical modelling of one such holographic dual in two dimensions-called the SYK model-as realised in graphene. The project will attack the theory from two sides-numerical modelling electron wave functions on graphene wafers and semi-analytic modelling using the Dirac equation from elementary particle theory. The work will support a possible experiment.
Supervisor: Prof Ian Moss
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Dust in the Wind: new insights into the impact of supermassive black holes with the James Webb Space Telescope (JWST)
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 multi-wavelength datasets from other modern telescopes to uncover dusty winds emanating from these AGNs, and quantitatively constrain their mass and energy outflow rates. You will compare the JWST images to advanced simulations of the AGN environment, and add in information from JWST spectroscopy to understand the interplay between black holes 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 with the topics of AGN science and infra-red astronomy is beneficial, but not required.
Links:
Newcastle University Astronomy research group
Supervisor: Dr David Rosario
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X-ray polarization: a new window to understand black holes
Black holes represent the most catastrophic end point of stellar evolution and posses the most extreme gravitational 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 depend 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
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The cosmic web as a laboratory for fundamental physics
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
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Cosmological galaxy surveys have in recent years begun to place field-leading constraints on the parameters of our model of the Universe. The statistical power of these data sets will only continue to grow in the coming years, with the Rubin Observatory Legacy Survey of Space and Time (LSST), slated to come online in 2023, set to increase the number of galaxies to the tens of billions. At the same time, exciting indications of potential cracks in the standard cosmological model (ΛCDM) have emerged, notably a discrepancy in the values of key cosmological parameters as measured in the early and late Universe. If confirmed, this could indicate the breakdown of ΛCDM as a universal standard model of cosmology.
Will LSST confirm ΛCDM, or will it point us towards new physics? To ensure a robust answer to this question, we need to significantly improve our understanding and treatment of the ways in which, on cosmological scales, galaxies behave not just as ways to trace the cosmic dark matter but as complex astrophysical objects.
In this PhD project, you will develop new modelling tools for and make novel measurements of two key astrophysical effects which impact cosmological measurements of gravitational lensing and cosmic structure: the intrinsic alignment between orientations and shapes of nearby galaxies due to tidal physics and environment effects, and the so-called ‘galaxy bias’ – the link between the galaxy distribution and the underlying dark matter field. In doing so, you will both ensure rigorous answers to burning cosmological questions and improve upon our understanding of the astrophysical behaviour of galaxies at a population level.
Supervisor: Dr Danielle Leonard
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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
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