Moving Detectors in Cavities

TL;DR

This paper investigates the effects of moving detectors in cavities, revealing that boundary effects and switching protocols significantly influence observed phenomena like the Unruh effect, independent of acceleration.

Contribution

It introduces a smooth switching approach to cavity interactions and clarifies misconceptions about acceleration-induced effects in quantum fields.

Findings

Pathological resonances due to abrupt boundaries are mitigated by smooth switching.

Emission/absorption ratios can be arbitrarily high, independent of acceleration.

Inertial and accelerated trajectories can produce similar pseudo-temperatures.

Abstract

We consider two-level detectors, coupled to a quantum scalar field, moving inside cavities. We highlight some pathological resonant effects due to abrupt boundaries, and decide to describe the cavity by switching smoothly the interaction by a time-dependent gate-like function. Considering uniformly accelerated trajectories, we show that some specific choices of non-adiabatic switching have led to hazardous interpretations about the enhancement of the Unruh effect in cavities. More specifically, we show that the emission/absorption ratio takes arbitrary high values according to the emitted quanta properties and to the transients undergone at the entrance and the exit of the cavity, {\it independently of the acceleration}. An explicit example is provided where we show that inertial and uniformly accelerated world-lines can even lead to the same ``pseudo-temperature''.