The Unruh Quantum Otto Engine

TL;DR

This paper proposes a quantum Otto engine that utilizes the Unruh effect, where a qubit interacts with the quantum vacuum, enabling heat exchange and work production based on acceleration-induced thermal properties.

Contribution

It introduces a fully quantum Otto cycle leveraging the Unruh effect with a single qubit, analyzing efficiency and operational conditions based on initial states and acceleration.

Findings

Quantum vacuum can exchange heat with a qubit.

Work can be extracted from the vacuum via acceleration.

Efficiency depends on initial populations and acceleration range.

Abstract

We introduce a quantum heat engine performing an Otto cycle by using the thermal properties of the quantum vacuum. Since Hawking and Unruh, it has been established that the vacuum space, either near a black hole or for an accelerated observer, behaves as a bath of thermal radiation. In this work, we present a fully quantum Otto cycle, which relies on the Unruh effect for a single quantum bit (qubit) in contact with quantum vacuum fluctuations. By using the notions of quantum thermodynamics and perturbation theory we obtain that the quantum vacuum can exchange heat and produce work on the qubit. Moreover, we obtain the efficiency and derive the conditions to have both a thermodynamic and a kinematic cycle in terms of the initial populations of the excited state, which define a range of allowed accelerations for the Unruh engine.