A stochastic heat engine using an active particle

TL;DR

This paper explores a microscopic Stirling's engine powered by an active particle, demonstrating that activity enhances efficiency and performance, with analytical and simulation results confirming the benefits of increased activity strength.

Contribution

It introduces a novel active-particle-based microscopic heat engine and analyzes how activity influences its efficiency and optimal operation conditions.

Findings

Activity increases engine efficiency across all cycle times.

Efficiency improves with higher activity strength.

Optimal operation region identified using efficient power metric.

Abstract

The topic of microscopic heat engine has undergone intensive research in recent years. Microscopic heat engines can exploit thermal as well as active fluctuations to extract thermodynamic work. We investigate the properties of a microscopic Stirling's engine that uses an active (self-propelling) particle as a working substance, in contact with two thermal baths. It is shown that the presence of activity leads to an enhanced performance of the engine. The efficiency can be improved by increasing the activity strength for all cycle time, including the non-quasistatic regime. We verify that the analytical results agree very well with our simulations. The variation of efficiency with the temperature difference between the two thermal baths has also been explored. The optimum region of operation of the engine has been deduced, by using its efficient power as a quantifier. Finally, a simple model is provided that emulates the behaviour of a flywheel driven by this engine.