Quantum and Information Thermodynamics: A Unifying Framework based on Repeated Interactions

TL;DR

This paper introduces a unified thermodynamic framework based on repeated interactions with nonequilibrium units, enabling analysis of quantum and classical systems, and clarifying the roles of different reservoirs and quantum resources.

Contribution

It develops a comprehensive framework for quantum and classical thermodynamics using repeated interactions, unifying various concepts and analyzing quantum resources' impact on work extraction.

Findings

The framework models nonequilibrium reservoirs as resources of free energy.

Quantum resources do not increase maximum work extraction compared to classical resources.

It provides thermodynamic interpretations for master equations, Maxwell's demon, and other systems.

Abstract

We expand the standard thermodynamic framework of a system coupled to a thermal reservoir by considering a stream of independently prepared units repeatedly put into contact with the system. These units can be in any nonequilibrium state and interact with the system with an arbitrary strength and duration. We show that this stream constitutes an effective resource of nonequilibrium free energy and identify the conditions under which it behaves as a heat, work or information reservoir. We also show that this setup provides a natural framework to analyze information erasure ("Landauer's principle") and feedback controlled systems ("Maxwell's demon"). In the limit of a short system-unit interaction time, we further demonstrate that this setup can be used to provide a thermodynamically sound interpretation to many effective master equations. We discuss how non-autonomously driven systems, micromasers, lasing without inversion, and the electronic Maxwell demon, can be thermodynamically analyzed within our framework. While the present framework accounts for quantum features (e.g. squeezing, entanglement, coherence), we also show that quantum resources do not offer any advantage compared to classical ones in terms of the maximum extractable work.