Role of Asymmetry in the Performance Optimization of a Relativistic Quantum Otto Engine

TL;DR

This paper analytically examines how asymmetry in adiabatic processes influences the efficiency and performance of a relativistic quantum Otto engine driven by a time-dependent harmonic oscillator.

Contribution

It introduces an analytical framework to study the effects of asymmetry on the relativistic quantum Otto cycle's efficiency and operational regimes, highlighting the impact of oscillator velocity.

Findings

Efficiency approaches unity in sudden compression scenario.

Efficiency is limited to one-half in sudden expansion scenario.

Increasing oscillator velocity enhances work output and expands the engine operational region.

Abstract

We present an analytical study of the relativistic quantum Otto cycle driven by a time-dependent harmonic oscillator. By imposing an asymmetry on the two adiabatic processes of this cycle, we obtain distinct scenarios of sudden compression and sudden expansion, and analyze how asymmetry affects the performance of the relativistic quantum Otto engine. By leveraging the Omega function as a unified performance metric, we analytically characterize the efficiency in both scenarios. Our findings demonstrate that the efficiency approaches unity in the sudden compression case, while it is restricted to one-half for the sudden expansion case. Furthermore, we investigate the impact of increasing oscillator velocity on the extracted work and identify parameter regimes where either sudden compression or sudden expansion dominates. Additionally, we examine the optimal operating point using parametric efficiency-work plots, whose loop-shaped structure shows that increasing oscillator velocity enhances both work output and efficiency. Finally, through a detailed phase diagram analysis of the Otto cycle, we observe that the operational region corresponding to the engine mode expands with increasing oscillator velocity, while the refrigeration regime shrinks correspondingly.