Optimizing autonomous thermal machines powered by energetic coherence

TL;DR

This paper investigates how quantum coherence influences the performance of nanoscale thermal machines, revealing that coherence can both enhance and hinder their operation, depending on the context.

Contribution

It provides a detailed analysis of the role of energy basis coherence in small thermal machines, highlighting conditions under which coherence improves or impairs performance.

Findings

Coherence can enhance heat engine and refrigerator performance.

Input coherence can enable machines to operate in otherwise forbidden regimes.

In some cases, coherence can be detrimental to machine efficiency.

Abstract

The characterization and control of quantum effects in the performance of thermodynamic tasks may open new avenues for small thermal machines working in the nanoscale. We study the impact of coherence in the energy basis in the operation of a small thermal machine which can act either as a heat engine or as a refrigerator. We show that input coherence may enhance the machine performance and allow it to operate in otherwise forbidden regimes. Moreover, our results also indicate that, in some cases, coherence may also be detrimental, rendering optimization of particular models a crucial task for benefiting from coherence-induced enhancements.