Microscopic dynamical Casimir effect

TL;DR

This paper investigates the microscopic dynamical Casimir effect caused by an atom's oscillation, revealing photon emission mechanisms depending on the oscillation frequency relative to atomic transition frequency.

Contribution

It provides a detailed analysis of photon emission processes from an oscillating atom, linking microscopic effects to the macroscopic dynamical Casimir effect.

Findings

Photon emission when oscillation frequency exceeds atomic transition frequency.

Photon pair production when oscillation frequency is below atomic transition frequency.

Connection established between microscopic and macroscopic dynamical Casimir effects.

Abstract

We consider an atom in its ground state undergoing a non-relativistic oscillation in free space. The interaction with the electromagnetic quantum vacuum leads to two effects to leading order in perturbation theory. When the mechanical frequency is larger than the atomic transition frequency, the dominant effect is the motion-induced transition to an excited state with the emission of a photon carrying the excess energy. We compute the angular distribution of emitted photons and the excitation rate. On the other hand, when the mechanical frequency is smaller than the transition frequency, the leading-order effect is the parametric emission of photon pairs, which constitutes the microscopic counterpart of the dynamical Casimir effect. We discuss the properties of the microscopic dynamical Casimir effect and build a connection with the photon production by an oscillating macroscopic metallic mirror.