Probing the Unruh effect with an accelerated extended system

TL;DR

This paper demonstrates that an extended system uniformly accelerated in a vacuum state thermalizes to a Gibbs state at the Unruh temperature, confirming the physical reality of the Unruh effect for extended systems.

Contribution

It provides a dynamical proof that extended systems experience thermalization consistent with the Unruh effect, addressing previous doubts about its validity.

Findings

Extended systems thermalize to a Gibbs state at Unruh temperature.

The vacuum acts as a legitimate thermal reservoir for accelerated systems.

Confirms the physical reality of the Unruh effect for extended systems.

Abstract

It has been proved in the context of quantum fields in Minkowski spacetime that the vacuum state is a thermal state according to uniformly accelerated observers -- a seminal result known as the Unruh effect. Recent claims, however, have challenged the validity of this result for extended systems, thus casting doubts on its physical reality. Here, we study the dynamics of an extended system, uniformly accelerated in the vacuum. We show that its reduced density matrix evolves to a Gibbs thermal state with local temperature given by the Unruh temperature. This proves that the vacuum state does induce thermalization of an accelerated extended system -- which is all one can expect of a legitimate thermal reservoir.