Unruh quantum Otto engine in the presence of a reflecting boundary

TL;DR

This paper models a relativistic quantum Otto engine with a qubit interacting with a scalar field near a reflecting boundary, showing boundary effects modify response functions and work output but not efficiency.

Contribution

It introduces a new boundary-influenced quantum Otto engine model, analyzing how a reflecting boundary affects the qubit's response and engine performance.

Findings

Boundary modifies the qubit's response function.

Work output decreases with boundary proximity.

Engine efficiency remains unchanged despite boundary effects.

Abstract

We introduce a new model of relativistic quantum analogue of the classical Otto engine in the presence of a perfectly reflecting boundary. A single qubit acts as the working substance interacting with a massless quantum scalar field, with the boundary obeying the Dirichlet condition. The quantum vacuum serves as a thermal bath through the Unruh effect. We observe that the response function of the qubit gets significantly modified by the presence of the reflecting boundary. From the structure of the correlation function, we find that three different cases emerge, namely, the intermediate boundary regime, the near boundary regime, and the far boundary regime. As expected, the correlation in the far boundary regime approaches that of the Unruh quantum Otto engine (UQOE) when the reflecting boundary goes to infinity. The effect of the reflecting boundary is manifested through the reduction of the critical excitation probability of the qubit and the work output of the engine. In spite of the reduced work output, the efficiency of the engine remains unaltered even in the presence of the boundary.