Effects of the non-Markovianity and non-Gaussianity of active environmental noises on engine performance

TL;DR

This paper systematically investigates how non-Gaussian and non-Markovian active environmental noises influence engine performance, revealing that non-Gaussianity is generally irrelevant while non-Markovianity and their combination can enhance performance.

Contribution

It provides a comprehensive analysis of the roles of non-Gaussianity and non-Markovianity in active noise, clarifying their impact on different types of engine dynamics.

Findings

Non-Gaussianity does not affect engine performance with linear forces.

Non-Markovianity influences engine performance in linear force systems.

Both non-Gaussianity and non-Markovianity enhance performance in nonlinear force systems.

Abstract

An active environment is a reservoir containing \emph{active} materials, such as bacteria and Janus particles. Given the self-propelled motion of these materials, powered by chemical energy, an active environment has unique, nonequilibrium environmental noise. Recently, studies on engines that harvest energy from active environments have attracted a great deal of attention because the theoretical and experimental findings indicate that these engines outperform conventional ones. Studies have explored the features of active environments essential for outperformance, such as the non-Gaussian or non-Markovian nature of the active noise. However, these features have not yet been systematically investigated in a general setting. Therefore, we systematically study the effects of the non-Gaussianity and non-Markovianity of active noise on engine performance. We show that non-Gaussianity is irrelevant to the performance of an engine driven by {any linear force (including a harmonic trap) regardless of time dependency}, whereas non-Markovianity is relevant. However, for a system driven by a general nonlinear force, both non-Gaussianity and non-Markovianity enhance engine performance. Also, the memory effect of an active reservoir should be considered when fabricating a cyclic engine.