Casimir-Polder force fluctuations as spatial probes of dissipation in metals

TL;DR

This paper investigates how spatial fluctuations in the Casimir-Polder force above metals reveal the role of electronic dissipation, showing significant dependence on material relaxation and temperature effects.

Contribution

It demonstrates that force fluctuations are highly sensitive to electron relaxation in metals and vary significantly with temperature, providing a novel probe of dissipation mechanisms.

Findings

Force fluctuations depend on electron relaxation in metals.

Fluctuations decrease sharply at large distances at nonzero temperature.

Magnitude of fluctuations can differ by orders of magnitude based on dissipation.

Abstract

We study the spatial fluctuations of the Casimir-Polder force experienced by an atom or a small sphere moved above a metallic plate at fixed separation distance. We demonstrate that unlike the mean force, the magnitude of these fluctuations crucially relies on the relaxation of conduction electron in the metallic bulk, and even achieves values that differ by orders of magnitude depending on the amount of dissipation. We also discover that fluctuations suffer a spectacular decrease at large distances in the case of nonzero temperature.