arXiv subjects

Thomas A. Flynn

Publications and source records attributed to Thomas A. Flynn.

3 recordsLinked to original sources

arXiv2026

DSLHyPE-a DSL kernel language for the Exascale Hyperbolic PDE Engine ExaHyPE

We introduce a bilingual domain-specific language (DSL) for modelling compute kernels within a generic solver for hyperbolic partial differential equations (PDEs). Users express PDE terms, i.e.~the underlying physics, in a familiar native language such as C or C++, while the numerical scheme is specified in a Python-embedded DSL, DSLHyPE. DSLHyPE's compiler lowers the Python description to MLIR and introduces a translation pass that integrates it with native code likewise mapped to MLIR. Our approach keeps the numerical representation and the physics implementation separate for as long as possible, while delegating optimization to the compiler through existing MLIR optimization passes. This separation of concerns benefits researchers developing numerical schemes on top of existing PDE implementations or with applications involving nonlinear systems whose PDE terms must solve PDEs themselves. We demonstrate the feasibility of the approach using a gravitational-wave solver and a matter-evolution solver on x86 processors and H200 GPUs.

cs.MS↗

arXiv2023

Trapped Imbalanced Quantum Droplets

A two-component quantum droplet is an attractive mixture of ultracold bosons stabilised against collapse by quantum fluctuations. Commonly, two-component quantum droplets are studied within a balanced mixture. However, the mixture can be imbalanced resulting in a lower energy but less stably bound droplet, or even a droplet submerged in a gas. This work focuses on the experimentally relevant question: how are imbalanced droplets modified by harmonic trap potentials? Droplet ground states and breathing modes are analysed across the two-dimensional parameter space of imbalance and trap strength. The robustness of the droplet imbalance is also studied by releasing the droplet from the trap, demonstrating that this can lead to the creation of free-space, imbalanced droplets.

cond-mat.quant-gas↗

arXiv2023

Quantum Droplets in Imbalanced Atomic Mixtures

Quantum droplets are a quantum analogue to classical fluid droplets in that they are self-bound and display liquid-like properties -- such as incompressibility and surface tension -- though their stability is the result of quantum fluctuations. One of the major systems for observing quantum droplets is two-component Bose gases. Two-component droplets are typically considered to be balanced, having a fixed ratio between the densities of the two component. This work goes beyond the fixed density ratio by investigating spherical droplets in imbalanced mixtures. With increasing imbalance, the droplet is able to lower its energy up to a limit, at which point the droplet becomes saturated with the atoms of the majority component and any further atoms added to this component cannot bind to the droplet. Analysing the breathing mode dynamics of imbalanced droplets indicates that the droplet can emit particles, as in balanced mixtures, but the imbalance leads to an intricate superposition of multiple simultaneously decaying collective oscillations.

cond-mat.quant-gas↗