Dynamical heat engines with non--Markovian reservoirs

TL;DR

This paper explores how non-Markovian reservoirs enable quantum heat engines through dynamic coupling modulation, highlighting the necessity of non-Markovianity and structured environments for efficiency.

Contribution

It demonstrates that non-Markovianity is essential for quantum heat engines with modulated couplings and identifies environment structures that optimize efficiency.

Findings

Non-Markovian baths are necessary for quantum heat engines.

Structured environments can approach Carnot efficiency.

Dynamic coupling modulation enables quantum heat engine operation.

Abstract

We discuss whether, and under which conditions, it is possible to realize a heat engine simply by dynamically modulating the couplings between the quantum working medium and thermal reservoirs. For that purpose, we consider the paradigmatic model of a quantum harmonic oscillator, exposed to a minimal modulation, that is, a monochromatic driving of the coupling to only one of the thermal baths. We demonstrate, at any order in the system/bath coupling strength, that in this setup non--Markovianity of the bath is a necessary condition to obtain a heat engine. In addition, we identify suitable structured environments for the engine to approach the ideal Carnot efficiency. Our results open up new possibilities for the use of non--Markovian open quantum systems for the construction and optimization of quantum thermal machines.