Fluctuations of the Casimir potential above a disordered medium

TL;DR

This paper investigates the statistical fluctuations of the Casimir potential near a disordered dielectric medium, revealing how single and multiple scattering processes influence potential variability.

Contribution

It provides a microscopic analysis of Casimir potential fluctuations, highlighting the role of scattering processes in disordered media and their impact on potential variability.

Findings

Fluctuations are mainly governed by scattering on a single heterogeneity.

Potential fluctuations can surpass average values in certain regimes.

Multiple scattering becomes significant in denser disorder.

Abstract

We study the statistical fluctuations of the Casimir potential felt by an atom approaching a dielectric disordered medium. Starting from a microscopic model for the disorder, we calculate the variance of potential fluctuations in the limit of a weak density of heterogeneities. We show that fluctuations are essentially governed by scattering of the radiation on a single heterogeneity, and discuss in which limits they become larger than the average value predicted by effective medium theory. Finally, for denser disorder we show that multiple scattering processes become relevant.