Relativity and quantum optics: accelerated atoms in optical cavities

TL;DR

This paper investigates how relativistic motion of atoms affects their interaction with optical cavities, revealing that common approximations in quantum optics fail under relativistic conditions, especially in the weak coupling regime.

Contribution

It critically assesses the validity of standard quantum optics approximations for relativistically moving atoms crossing optical cavities, highlighting their limitations.

Findings

Single- and few-mode approximations are inaccurate in relativistic regimes.

1+1D cavity models do not reliably represent 3+1D relativistic scenarios.

Standard approximations break down even at weak coupling in relativistic contexts.

Abstract

We analyze the physics of accelerated particle detectors (such as atoms) crossing optical cavities. In particular we focus on the detector response as well as on the energy signature that the detectors imprint in the cavities. In doing so, we examine to what extent the usual approximations made in quantum optics in cavities (such as the single-mode approximation, or the dimensional reduction of 3+1D cavities to simplified 1+1D setups) are acceptable when the atoms move in relativistic trajectories. We also study the dependence of these approximations on the state of the atoms and the relativistic nature of the trajectory. We find that, on very general grounds, and already in the weak coupling limit, single- and few-mode approximations, as well as 1+1D dimensional reductions, yield incorrect results when relativistic scenarios are considered.