Fulling-Davies-Unruh effect and spontaneous excitation of an accelerated atom interacting with a quantum scalar field

TL;DR

This paper explores how a uniformly accelerated atom interacts with a scalar field, demonstrating that the Unruh effect can be understood as the atom perceiving a thermal bath at a specific temperature in the coaccelerated frame.

Contribution

It provides a detailed analysis of the spontaneous excitation of an accelerated atom, linking the Unruh effect to thermal behavior in the coaccelerated frame, and offers new insights into this quantum phenomenon.

Findings

The excitation rate matches the thermal bath prediction at the Unruh temperature.

The analysis confirms the Unruh effect as a thermal phenomenon in the coaccelerated frame.

Provides a new example to understand the physical implications of the Unruh effect.

Abstract

We investigate, from the point of view of a coaccelerated frame, the spontaneous excitation of a uniformly accelerated two-level atom interacting with a scalar field in a thermal state at a finite temperature $T$ and show that the same spontaneous excitation rate for the uniformly accelerated atom in the Minkowski vacuum obtained in the inertial frame can only be recovered in the coaccelerated frame assuming a thermal bath at the Fulling-Davies-Unruh temperature $T_{FDU}=a/2\pi$ for what appears to be the Minkowski vacuum to the inertial observer. Our discussion provides another example of a physical process different from those examined before in the literature to better understand the Fulling-Davies-Unruh effect.