Modified atomic decay rate near absorptive scatterers at finite temperature

TL;DR

This paper models how the decay rate of an excited atom is affected by nearby absorptive, thermally excited scatterers, revealing the interplay of absorption, scattering, and thermal radiation effects.

Contribution

It provides analytical expressions for decay rate modifications near a medium of thermally excited scatterers, incorporating absorption and thermal effects.

Findings

Decay rate depends on distance and medium properties.

Absorption and thermal radiation can counteract each other.

Comparison with effective-medium theory highlights discrete scatterer effects.

Abstract

The change in the decay rate of an excited atom that is brought about by extinction and thermal-radiation effects in a nearby dielectric medium is determined from a quantummechanical model. The medium is a collection of randomly distributed thermally-excited spherical scatterers with absorptive properties. The modification of the decay rate is described by a set of correction functions for which analytical expressions are obtained as sums over contributions from the multipole moments of the scatterers. The results for the modified decay rate as a function of the distance between the excited atom and the dielectric medium show the influence of absorption, scattering and thermal-radiation processes. Some of these processes are found to be mutually counteractive. The changes in the decay rate are compared to those following from an effective-medium theory in which the discrete scatterers are replaced by a continuum.