Quantum machines powered by correlated baths

TL;DR

This paper investigates how classical and quantum correlations in reservoirs influence the performance of quantum thermal machines, analyzing heat, work, and correlations through a collisional model framework.

Contribution

It introduces a framework for studying correlated reservoirs in quantum machines and identifies the swap transformation as optimal for heat and work transfer.

Findings

Total swap transformation maximizes heat and work transfer.

Correlations among constituents affect machine performance.

Optimal unitaries depend on the nature of correlations.

Abstract

We consider thermal machines powered by locally equilibrium reservoirs that share classical or quantum correlations. The reservoirs are modelled by the so-called collisional model or repeated interactions model. In our framework, two reservoir particles, initially prepared in a thermal state, are correlated through a unitary transformation and afterwards interact locally with the two quantum subsystems which form the working fluid. For a particular class of unitaries, we show how the transformation applied to the reservoir particles affects the amount of heat transferred and the work produced. We then compute the distribution of heat and work when the unitary is chosen randomly, proving that the total swap transformation is the optimal one. Finally, we analyse the performance of the machines in terms of classical and quantum correlations established among the microscopic constituents of the machine.