Quantum Performance of Thermal Machines over Many Cycles

TL;DR

This paper investigates the long-term performance of quantum heat engines over multiple cycles, revealing that total work can surpass simple proportionality and identifying scenarios with quantum advantages.

Contribution

It challenges the single-cycle analysis by showing multi-cycle optimization can lead to quantum enhancements in engine performance.

Findings

Total work need not be proportional to cycle count

Multi-cycle optimization reveals quantum advantages

Demonstration with a quantum Otto engine

Abstract

The performance of quantum heat engines is generally based on the analysis of a single cycle. We challenge this approach by showing that the total work performed by a quantum engine need not be proportional to the number of cycles. Furthermore, optimizing the engine over multiple cycles leads to the identification of scenarios with a quantum enhancement. We demonstrate our findings with a quantum Otto engine based on a two-level system as the working substance that supplies power to an external oscillator.