Ambient temperature versus ambient acceleration in the circular motion Unruh effect

TL;DR

This paper investigates the Unruh effect for circular motion, comparing thermal bath and accelerated circular motion, and finds that observers can distinguish between these scenarios based on local measurements.

Contribution

It extends the understanding of the Unruh effect by analyzing the differences in field experiences for circular motion in thermal and accelerated frames.

Findings

Observers can differentiate between thermal and accelerated circular motion cases.

The duality between acceleration and temperature is not robust in circular motion.

Local measurements reveal differences in the field experiences for the two scenarios.

Abstract

It is well known that the experience of a linearly accelerated observer with acceleration $a$, interacting with a massless scalar field in its vacuum state in $3+1$ Minkowski spacetime, is identical to that of a static observer interacting with a massless scalar field in a thermal state of temperature $a/2\pi$ in $3+1$ Minkowski spacetime. We study the robustness of this duality by comparing an observer undergoing circular motion in a thermal bath with an observer that undergoes circular motion around a linearly accelerated trajectory. We find that in most regimes, observers in these two cases experience the field in different ways, and are generally able to tell the difference between the two cases by measuring observables localized along their trajectories.