Within the School of Physics & Astronomy (Division of Natural Sciences) we are particularly inviting applications to the following projects:
Competing order parameters and multi criticality – Dr Sam Carr (S.T.Carr@kent.ac.uk)
Multi-critical points occur when more than two phases of matter meet at the same point in parameter space. Each phase is described by its own order parameter, so at a multi-critical point, one has competing order parameters from each phase. Around a tetra-critical point, there exists phases where more than one of these order parameters is non-zero. These are well studied from the point of view of the criticality (see e.g. ) however a full understanding of the phases themselves is lacking — indeed in  it was shown in a certain class of models with tetra-critical points that the co-existence phases can not extend down to zero temperature so one has the unusual situation where one of the order parameters becomes non-zero as temperature is increased — a phenomena known as order-by-disorder as it is driven by entropy, not energy. In this project, we will analyse phase diagrams of model systems in full beyond mean field theory. This may then be extended to wider classes of models with competing order to fully understand the link between the phases themselves and the nature of the multi-critical points that separate them. The project is theoretical in nature.
Computational multiscale modelling of radiosensitisation mechanisms of metal nanoparticles – Professor Nigel Mason (N.J.Mason@kent.ac.uk)
The main objective of this project is to advance our nanoscopic and molecular-level understanding of the ion-irradiation-induced phenomena involving radiosensitising coated metal nanoparticles (NPs). This will include study of (i) the structural characterization of experimentally relevant NPs in explicit molecular environments; (ii) ion-irradiation-induced transformations of NPs (including eventual fragmentation of metal cores and organic coatings) and (iii) the impact of these properties on the formation and transport of secondary electrons, free radicals and other reactive species in the vicinity of irradiated NPs. These phenomena will be explored by means of advanced multiscale computer simulations combining classical molecular dynamics (MD), analytical models, irradiation driven and reactive MD - the advanced computational methodology for the molecular-level description of chemical and irradiation-driven transformations. The results obtained in this project will provide the essential nanoscopic insights needed for the smart synthesis of NPs with enhanced/optimized radiosensitising properties for use in the clinic. The project involves a collaboration between the University of Kent and MBN Research Center in Frankfurt Germany, the student is expected to spend at least two months per year at MBN Research Center as well as attending appropriate conferences and workshops in which nanoscale processes and radiation damage are discussed.
Coordination Without Communication: Quantum-Assisted Rendezvous Strategies – Dr Jorge Quintanilla (email@example.com)
Rendezvous is a classic problem in operations research first formulated by Alpern in 1976. There are many variations by they all revolve around the need for two or more parties to find each other without communicating between them. Applications include search-and-rescue, telecommunications and covert operations.
Recently, it has been noted that Physics has something to add to the mixture: if two parties trying to solve a rendezvous problem share a quantum resource (in other words, they are in possession of physical systems that are quantum-mechanically entangled) then there are algorithms they can use that beat the optimal non-quantum strategies. In this project you will use quantum computers to search for optimal rendez-vous strategies making use of this recently discovered quantum advantage.
Developing Powerful Custom-Made Swept Sources for OCT Using Polygon Mirror Based Wavelength – Dr George Dobre (G.Dobre@kent.ac.uk)
Polygon mirror based spectral filters provide a versatile method of repeated tuning through broadband spectra for Optical Coherence Tomography imaging in the laboratory. They are at the heart of swept sources capable of operation in any wavelength range at speeds of hundreds of kHz with the added advantage of running several sources from the same polygon mirror element.
Investigating polygon mirror swept sources for use in OCT imaging involves the design and alignment of such PM spectral filters including bespoke optical design, which we have shown has a significant effect on the bandwidth and linewidth, as well as the maximum power throughput.
High pressure physics of conductivity to advance energy materials – Dr Emma Pugh (firstname.lastname@example.org) and Dr Mountjoy (email@example.com)
The motivation for this PhD project in condensed matter physics is to exploit high pressures as a means to modify conductivity in energy materials. Such materials, like battery cathodes, are essential for the ongoing transition to a carbon net-zero energy economy. The PhD project will involve using high pressure apparatus in the Physics of Quantum Materials (PQM) research group, which has a unique configuration of diamond anvil cells, laser, and optical spectrometer. Conductivity will be studied via resistivity measurements at ambient temperature for pressures up to 10 GPa (100,000 atmospheres). Computational modelling will be done using the School’s Tor computing cluster to simulate compression of the lattice structure under high pressure. It will be invaluable to compare with and undertake neutron and x-ray scattering studies at the national x-ray synchrotron and neutron source laboratories (Diamond and Rutherford Appleton) or overseas centres. The observed changes to conductivity can be used to understand how to optimise the lattice for conductivity in future energy applications.
Materials for low-energy computing technologies – Dr Silvia Ramos (S.Ramos-Perez@kent.ac.uk)
The explosion in sophisticated uses of computer power (e.g. artificial intelligence and machine learning applications) is transforming the way we live and work. However, current computer technologies do this at a very high energy cost. It has hence become an important technological challenge to find new technologies that are optimised for this type of applications and can do it with a lower energy consumption. The starting point for the development of such technologies is the discovery and characterisation of new materials that will underpin new computer architectures. This experimental project will use state-of-the-art synchrotron spectroscopy techniques to investigate electronic properties and atomic structure in chalcogenide based materials.
Multimodality optoacoustic remote sensing/optical coherence tomography for in-vivo, real-time imaging of the human eye - Dr Adrian Bradu (A.Bradu@kent.ac.uk)
In ophthalmology, functional changes, such as the oxygenation of the retinal tissue, precede structural changes, which are very often first observed using the currently available technologies, therefore having the capability to detect them earlier is of paramount importance. Nowadays, several imaging techniques including Optical Coherence Tomography (OCT), which steadily is becoming the gold standard, in producing structural images are used for diagnosing eye diseases in humans. However, none of these techniques is capable to provide accurate oxygen saturation maps of the retinal tissue, critical in investigating major blinding eye diseases such as diabetic retinopathy and age-related macular degeneration. One of the imaging techniques which has the capability to provide oxygenation maps of the biological tissue is opto-acoustic tomography (OAT). Unfortunately, OAT requires contact between the instrument and the tissue, therefore it is not suitable for in-vivo imaging the eye. Recently, a novel technique based on OAT, opto-acoustic remote sensing (OARS), not requiring contact with the tissue, has been demonstrated. Through this project, the capability of OARS to deliver retinal oxygenation maps of the eye’s retina will be evaluated.
Technology for Biomedical Imaging through Fibre Probes – Dr Michael Hughes (M.R.Hughes@kent.ac.uk)
In this project you will develop technology for advanced imaging through thin fibre bundle probes. Fibre bundles are used as conduits for imaging in constrained spaces and are the basis of techniques such as fluorescence endomicroscopy as well as recently developed approaches for coherent and holographic fibre imaging. The project will focus on developing computational imaging techniques to enable high-resolution imaging and numerical refocusing. This will involve assembling and testing new optical systems, developing software, and working with collaborators to apply the technology to applications in medicine and biosciences such as live cell imaging and water quality assessment. The PhD will suit someone with a degree in engineering, physics or computing and in an interest in building new imaging technology.
Ultrafast tunable laser for optical coherence tomography – Professor Adrian Podoleanu (firstname.lastname@example.org)
Research will focus on innovative solutions for fast, narrow linewidth, stable phase and wide tuning bandwidth swept sources for optical coherence tomography.
The student will address the difficult compromise between speed of acquisition, needed to reduce the distorting effects of organ movement, with the tuning bandwidth, as the larger the bandwidth, the better the axial resolution. If such a challenge can be addressed, then better diagnostic technology can be made available.
Unravelling Strong Correlations in Twisted 2D Multilayers – Dr Gunnar Moller (G.Moller@kent.ac.uk)
Twisted graphene multilayers have been heralded for the discovery of new types of correlated insulators and superconducting phases, triggering a wave of excitement about these spectacular new regimes of strong correlation physics. A small twist between two stacked graphene layers leads to huge ‘moiré’ unit cells with 1000s of atoms, but only few degrees of freedom are relevant at low energies and reduce to a low-energy manifold of eight flat bands near the magic twist angle.
There has been much work on this system, but a definite quantitative understanding of these interacting regimes in multiband materials remains lacking. To unravel strong correlation physics in multiband models such as these, the idea for this project is to generalise the connected determinantal Monte-Carlo (cDet) approach. The cDet algorithm has already yielded definite answers in many difficult to understand regimes for the case of the single band Hubbard model.