Stochastic Floquet quantum heat engines and stochastic efficiencies

TL;DR

This paper develops a stochastic theoretical framework for Floquet quantum heat engines using quantum trajectories, analyzing efficiency fluctuations and comparing them with universal fluctuation theory predictions.

Contribution

It introduces a novel stochastic framework for Floquet quantum heat engines and investigates the fluctuation statistics of their efficiencies.

Findings

One efficiency's statistics match universal fluctuation theory.

The other efficiency's statistics deviate due to missing fluctuation theorems.

Identifies the role of fluctuation theorems in efficiency fluctuation statistics.

Abstract

Based on the notion of quantum trajectory, we present a stochastic theoretical framework for Floquet quantum heat engines. As an application, the large deviation functions of two types of stochastic efficiencies for a two-level Floquet quantum heat engine are investigated. We find that the statistics of one efficiency agree well with the predictions of the universal theory of efficiency fluctuations developed by Verley et al. [Phys. Rev. E {\bf 90}, 052145 (2014)], whereas the statistics of the other efficiency do not. The reason for this discrepancy is attributed to the lack of fluctuation theorems for the latter type of efficiency.