This is a project which is currently making use of HPC facilities at Newcastle University. It is active.
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This is a multi-faceted project addressing the non-equilibrium many-body dynamics of bosonic fields in the non-relativistic limit. It is interdisciplinary, spanning from ultracold atomic gases and photon fluids to astrophysical modelling and cosmological large-scale simulations. Each of these subfields is addressed with the approporiate variation of the relevant numerical code, with the common theme being the numerical dynamics of a generalised scheme, based on either a (nonlinear) Schroedinger equation, N-body classical simulations, or their hybridisation.
In the context of laboratory quantum gases (ultracold atomic gases, exciton-polariton superfluids), various state-of-the-art schemes (based, e.g. on Quantum-Field Theory, Kinetic Equations, Classical Field & Stochastic Modelling, Quantum Many-Body Theory) are used to model Bose-Einstein Condensation wirth thermal and quantum fluctuations and intrinsic nonlinear dynamics (solitons, vortices), as relevant for quantum technologies (quantum engines, quantum sensors, atomtronics architectures with Josephson junctions), with simulations extended to various superefluid mixtures, phase transition dynamics and superfluid turbulence (the latter also relevant to liquid helium experiments). The numerical modelling is based on the so-called Gross-Pitaevskii Equation, with fluctuations included by additional contributions, including stochastic noise terms and a self-consistently coupled quantum Boltzmann equation. Key topics addressed relate to the role of the thermal cloud, quantum vortex dynamics and implications for quantum engines, atomtronic and other quantum-technological sensors and a variety of experimental findings available from external collaborators ranging from quantum mixtures to controlled turbulence experiements and dynamics in the presence of long-range dipolar interactions.
In the cosmological context, analogous models are used to describe the elusive dark matter in the Universe, both within the prevailing N-body simulations Cold Dark Matter (CDM) model, and with the emerging Fuzzy Dark Matter (FDM) model, along with newly-proposed hybrid cold-fuzzy dark matter models within our group. In fact, despite the very different physical nature of these systems, and the highly distinct scales (from micrometers to kiloparsec) such modelling is methodologically closely analogous to the ultracold atomic gases modelling, with the main difference being that instead of an externally imposed trap, gravitational attraction plays the role of a self-consistently adjusted attractive potential; in this context CDM resembles the thermal cloud Boltzmann dynamics (both solved via N-body simulations), while FDM is analogous to the Gross-Pitaevskii description (and its stochastic generalisations).
In trying to validate the cosmological findings against observations, we also perform MCMC simulations of such and other related astrophysical models, analysing observational findings, such as galactic rotation curves, with the aim of statistically understanding which models provide a better fit to observations.
Fortran, Python, Julia and Matlab are adopted for the relevant numerical scripts and packages to model quantum/non-relativistic fluids in diverse setups with the state of the art alogrithms (GPPE, SPGPE, ZNG) and numerical methods (FFT, RK4, Time-Spliting method, classical Monte-Carlo on partilce sampling and MCMC, stochastic noises), with some of the scripts intended for OpenMP and GPU computations