Purcell-Dicke enhancement of the Casimir-Polder potential

¹ Physikalisches Institut, Albert-Ludwigs-Universität Freiburg - Hermann-Herder-Straße 3, 79104 Freiburg, Germany
² Freiburg Institute for Advanced Studies, Albert-Ludwigs-Universität Freiburg - Albertstraße 19, 79104 Freiburg, Germany

Received: 9 July 2018
Accepted: 19 October 2018

Abstract

The emission by an initially completely inverted ensemble of two-level atoms in the long-wavelength regime is simultaneously enhanced by both collective effects (Dicke effect) and dielectric environments (Purcell effect), thus giving rise to a combined Purcell–Dicke effect. We study this effect by treating the ensemble of N atoms as a single effective N + 1-level “Dicke atom” which couples to the environment-assisted quantum electrodynamic field. We find that an environment can indeed alter the superradiant emission dynamics, as exemplified using a perfectly conducting plate. As the emission acquires an additional anisotropy in the presence of the plate, we find an associated resonant Casimir-Polder potential for the atom that is collectively enhanced and that exhibits a superradiant burst in its dynamics. An additional tuneability of the effect is introduced by applying an external driving laser field.