Out-of-equilibrium quantum thermochemical engine with one-dimensional Bose gas

TL;DR

This paper investigates a quantum thermochemical engine using a 1D Bose gas, analyzing its performance in finite time, and reveals how chemical work and out-of-equilibrium dynamics influence efficiency and power trade-offs.

Contribution

It introduces a theoretical model of a quantum engine with interaction quenches and thermalization, highlighting the role of chemical work in out-of-equilibrium quantum thermodynamics.

Findings

Engine operates via chemical work driven by particle flow.

Maximum power achieved in out-of-equilibrium regime with reduced efficiency.

Maximum efficiency reached in quasistatic limit with zero power.

Abstract

We theoretically explore the finite-time performance of a quantum thermochemical engine using a harmonically trapped 1D Bose gas in the quasicondensate regime as the working fluid. Operating on an Otto cycle, the engine's unitary work strokes involve quenches of interatomic interactions, treating the fluid as a closed many-body quantum system evolving dynamically from an initial thermal state. During thermalization strokes, the fluid is an open system in diffusive contact with a reservoir, enabling both heat and particle exchange. Using a c--field approach, we demonstrate that the engine operates via chemical work, driven by particle flow from the hot reservoir. The engine's performance is analyzed in two regimes: (i) the out-of-equilibrium regime, maximizing power at reduced efficiency, and (ii) the quasistatic limit, achieving maximum efficiency but zero power due to slow driving. Remarkably, chemical work enables maximum efficiency even in sudden quench regime, offering a favorable trade-off between power and efficiency. Finally, we connect this work to prior research, showing that a zero-temperature adiabatic cycle provides an upper bound for efficiency and work at finite temperatures.