Conductivity of dielectric and thermal atom-wall interaction

TL;DR

This paper examines the impact of dielectric conductivity on the Casimir-Polder force, finding that including conductivity in models contradicts experimental data, suggesting it should be excluded from dielectric response models.

Contribution

It provides experimental-theoretical comparison showing that dielectric conductivity should not be included in Lifshitz theory models for accurate predictions.

Findings

Conductivity inclusion contradicts experimental data.

Excluding conductivity aligns with observations for dielectrics, semiconductors, and metals.

Supports revising dielectric response models in Casimir force calculations.

Abstract

We compare the experimental data of the first measurement of a temperature dependence of the Casimir-Polder force by Obrecht et al. [Phys. Rev. Lett. {\bf 98}, 063201 (2007)] with the theory taking into account small, but physically real, static conductivity of the dielectric substrate. The theory is found to be inconsistent with the data. The conclusion is drawn that the conductivity of dielectric materials should not be included in the model of the dielectric response in the Lifshitz theory. This conclusion obtained from the long separation measurement is consistent with related but different results obtained for semiconductors and metals at short separations.