Speaker
Description
Bose-Einstein condensation is a ubiquitous phenomenon, present across a multitude of physical scales, from coherence among some thousands of atoms, to macroscopic superfluidity in liquid helium, up to theorised superfluid-superconducting neutrons and protons responsible for observed glitches in neutron stars. At all of these scales, questions persist around the subject of non-equilibrium dynamics, turbulence, and dissipation, to which the quantum, non-linear nature of superfluidity introduce mechanisms and features intractable by classical approaches. Remarkably, since the inaugural achievement of Bose-Einstein condensation in an ultracold atomic gas in 1995, atomic superfluids have rapidly developed into a highly controllable and flexible platform to probe ever more diverse and complex superfluid phenomena. One system which was fundamental to the study of equilibrium, non-equilibrium, driven-response and dissipative dynamics of fluids in the development of classical thermodynamics, is the engine. Recently, we have seen atomic superfluid experiments demonstrate the feasibility of constructing an engine system in a real laboratory system. Inspired by the work of Simmons et al in their 2023 paper (PRR 5, L042009 (2023)), in collaboration with experimentalists at Aarhus University we present an investigation of a quantum engine, with a 39K atomic superfluid as the working fluid. We demonstrate efficiency and power performance characteristics subject to variations in compression and interaction strength ratio, as well as finite temperature. We note the rapid convergence of this system to its reversible limit efficiency in finite duration cycles, as well as a novel driving regime which allows simultaneous maximisation of efficiency and power of the cycle.