Comparison between experiment and theory for the thermal Casimir force

TL;DR

This paper compares experimental measurements of the thermal Casimir force with theoretical predictions, examining the validity of approximation methods and background effects in sphere-plate geometries.

Contribution

It provides a detailed analysis of the proximity force approximation's accuracy and discusses the use of fitting procedures in theory-experiment comparisons for large spherical lenses.

Findings

PFA results are compared with exact calculations where available

Background effects can influence thermal Casimir force measurements

Fitting procedures may improve theory-experiment agreement

Abstract

We analyze recent experiments on measuring the thermal Casimir force with account of possible background effects. Special attention is paid to the validity of the proximity force approximation (PFA) used in the comparison between the experimental data and computational results in experiments employing a sphere-plate geometry. The PFA results are compared with the exact results where they are available. The possibility to use fitting procedures in theory-experiment comparison is discussed. On this basis we reconsider experiments exploiting spherical lenses of centimeter-size radii.