A Quantum Otto Engine with Shortcuts to Thermalization and Adiabaticity

TL;DR

This paper demonstrates that using shortcuts to adiabaticity and thermalization in a quantum Otto engine significantly improves its power and efficiency, enabling positive power output where traditional cycles fail.

Contribution

It introduces a hybrid protocol employing counter-diabatic driving for all cycle strokes, enhancing quantum engine performance beyond previous methods.

Findings

Enhanced power and efficiency with combined shortcuts.

Recovery of engine functionality in challenging parameter regimes.

Superior performance when controlling all three cycle strokes.

Abstract

We investigate the energetic advantage of accelerating a quantum harmonic oscillator Otto engine by use of shortcuts to adiabaticity (for the expansion and compression strokes) and to equilibrium (for the hot isochore), by means of counter-diabatic (CD) driving. By comparing various protocols with and without CD driving, we find that, applying both type of shortcuts leads to enhanced power and efficiency even after the driving costs are taken into account. The hybrid protocol not only retains its advantage in the limit cycle, but also recovers engine functionality (i.e. a positive power output) in parameter regimes where an uncontrolled, finite-time Otto cycle fails. We show that controlling three strokes of the cycle leads to an overall improvement of the performance metrics compared with controlling only the two adiabatic strokes. Moreover, we numerically calculate the limit cycle behavior of the engine and show that the engines with accelerated isochoric and adiabatic strokes display a superior power output in this mode of operation.