Characterizing irreversibility in open quantum systems

TL;DR

This paper reviews the concept of entropy production as a measure of irreversibility in open quantum systems, discussing its features, limitations, and implications for quantum thermodynamics and machine performance.

Contribution

It provides a comprehensive analysis of entropy production in quantum systems, highlighting its current limitations and potential for characterizing irreversibility.

Findings

Entropy production is a key measure of irreversibility.

Current formulations of entropy production have limitations.

Understanding irreversibility aids quantum thermodynamics and machine efficiency.

Abstract

Irreversibility is a fundamental concept with important implications at many levels. It pinpoints the fundamental difference between the intrinsically reversible microscopic equations of motion and the unidirectional arrow of time that emerges at the macroscopic level. More pragmatically, a full quantification of the degree of irreversibility of a given process can help in the characterisation of the performance of thermo-machines operating at the quantum level. Here, we review the concept of entropy production, which is commonly intended as {\it the} measure of thermodynamic irreversibility of a process, pinpointing the features and shortcomings of its current formulation.