The Casimir-Polder potential in the presence of a Fock state

TL;DR

This paper presents an explicit normal-mode calculation of the Casimir-Polder potential for a ground-state atom near a surface in the presence of a quantised external field, revealing features similar to excited-state forces.

Contribution

It provides an analytic, physically transparent model of driven Casimir-Polder potentials including retardation effects and arbitrary alignment configurations.

Findings

Potential shares features with excited-state Casimir-Polder forces

Analytic results include retardation effects

Applicable for any mutual alignment of dipole, field, and surface normal

Abstract

Atom-surface forces using excited states have a host of compelling applications, including repulsive and lateral forces. However, such states can be fragile and difficult to prepare. Here we report an explicit normal-mode based calculation of the Casimir-Polder potential between a ground-state atom and a non-dispersive surface in the presence of an external quantised field. The potential we derive shares some features with that of excited-state Casimir-Polder forces even though we consider a ground-state atom. Our work provides a physically transparent and intuitive picture of driven Casimir-Polder potentials, as well as expanding on previous investigations by providing analytic results that fully include retardation, as well as being applicable for any choice of mutual alignment of the atom's dipole moment, the external field, and the surface normal.