Steady-state coherence in multipartite quantum systems: its connection with thermodynamic quantities and impact on quantum thermal machines

TL;DR

This paper investigates how quantum coherence in multipartite systems influences thermodynamic quantities like work and heat in non-equilibrium steady states, providing insights for designing quantum thermal machines.

Contribution

It introduces a detailed analysis of coherence contributions to thermodynamics in multipartite quantum systems with non-local dissipation, and explores their impact on quantum thermal machine performance.

Findings

Non-local heat current linked to quantum coherence.

Work currents (local and non-local) are determined by coherence.

System can function as refrigerator, engine, or accelerator, depending on configuration.

Abstract

Understanding how coherence of quantum systems affects thermodynamic quantities, such as work and heat, is essential for harnessing quantumness effectively in thermal quantum technologies. Here, we study the unique contributions of quantum coherence among different subsystems of a multipartite system, specifically in non-equilibrium steady states, to work and heat currents. Our system comprises two coupled ensembles, each consisting of $N$ particles, interacting with two baths of different temperatures, respectively. The particles in an ensemble interact with their bath either simultaneously or sequentially, leading to non-local dissipation and enabling the decomposition of work and heat currents into local and non-local components.We find that the non-local heat current, as well as both the local and non-local work currents,are linked to the system quantum coherence. We provide explicit expressions of coherence-related quantities that determine the work currents under various intrasystem interactions.Our scheme is versatile, capable of functioning as a refrigerator, an engine, and an accelerator, with its performance being highly sensitive to the configuration settings. These findings establish a connection between thermodynamic quantities and quantum coherence, supplying valuable insights for the design of quantum thermal machines.