The role of quantum coherence in non-equilibrium entropy production

TL;DR

This paper investigates how quantum coherence influences entropy production in non-equilibrium quantum systems, revealing a distinct quantum contribution and analyzing spin systems using phase space methods.

Contribution

It introduces a formal division of entropy production into population and coherence contributions, highlighting the quantum-specific part in open-system dynamics.

Findings

Quantum coherence contributes uniquely to entropy production.

Population unbalances affect both entropy flux and production rate.

Decoherence impacts only the entropy production rate.

Abstract

Thermodynamic irreversibility is well characterized by the entropy production arising from non-equilibrium quantum processes. We show that the entropy production of a quantum system undergoing open-system dynamics can be formally split into a term that only depends on population unbalances, and one that is underpinned by quantum coherences. The population unbalances are found to contribute to both an entropy flux and an entropy production rate. The decoherence, on the other hand, contributes only to the entropy production rate. This allows us to identify a genuine quantum contribution to the entropy production in non-equilibrium quantum processes. We make use of such a division to address the open-system dynamics of a spin $J$ particle, which we describe in phase space through a spin-coherent representation.