The reaction coordinate mapping in quantum thermodynamics

TL;DR

This paper reviews the reaction coordinate method in quantum thermodynamics, which explicitly models strong system-reservoir interactions and non-Markovian effects, improving understanding of quantum heat engines.

Contribution

It provides an overview of the reaction coordinate approach, highlighting its ability to handle strong coupling and non-Markovian dynamics in quantum thermodynamics.

Findings

Strong coupling can be managed without degrading heat engine performance.

Reaction coordinate method captures system-reservoir correlations accurately.

Applicable to both discrete and continuous quantum heat engines.

Abstract

We present an overview of the reaction coordinate approach to handling strong system-reservoir interactions in quantum thermodynamics. This technique is based on incorporating a collective degree of freedom of the reservoir (the reaction coordinate) into an enlarged system Hamiltonian (the supersystem), which is then treated explicitly. The remaining residual reservoir degrees of freedom are traced out in the usual perturbative manner. The resulting description accurately accounts for strong system-reservoir coupling and/or non-Markovian effects over a wide range of parameters, including regimes in which there is a substantial generation of system-reservoir correlations. We discuss applications to both discrete stroke and continuously operating heat engines, as well as perspectives for additional developments. In particular, we find narrow regimes where strong coupling is not detrimental to the performance of continuously operating heat engines.