Quantum work extraction of a moving battery as a witness to Unruh thermality in high-dimensional spacetimes

We put forward a physical model of a uniformly accelerated Unruh-DeWitt battery and use quantum work extraction as a probe to witness the thermal nature of the Unruh effect in a high dimensional Minkowski spacetime. By means of the open quantum system approach, we investigate the maximal amount of quantum work extraction with respect to the acceleration-induced Unruh temperature, spacetime dimensionality, and field mass. It has been found that the steady amount of quantum work extraction in the asymptotic condition is just determined by the Unruh temperature in arbitrary dimensional spacetimes. The asymptotic behavior can demonstrate the global feature of Unruh thermality dependent on the Kubo-Martin-Schwinger condition. From a local viewpoint of the Unruh effect, we study the different ways for the dynamics of quantum work extraction when the battery gradually arrives at the same steady state. In the massless scalar field, the evolution with a small acceleration takes on a unique monotonicity in <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:mi>D</a:mi><a:mo>=</a:mo><a:mn>3</a:mn></a:mrow></a:math> dimensional spacetime and changes to a decaying oscillation for other higher dimensions. The increase in spacetime dimensionality can increase the energy storage capacity of the moving battery. If the mass of the scalar field is considered, the related quantum work extraction is so robust against the Unruh decoherence that the high values can keep for a very long time. The persistence of quantum work extraction is strengthened in higher dimensional spacetime.