Roughness corrections to the Casimir force: The importance of local surface slope

TL;DR

This study enhances the theoretical modeling of the Casimir force by incorporating finite conductivity and local surface slope effects, emphasizing the importance of detailed roughness characterization for accurate experimental comparisons.

Contribution

It introduces a method to include local surface slope effects in Casimir force calculations, improving agreement with experimental data at short separations.

Findings

Local surface slopes significantly affect the Casimir force.

Including lateral roughness dimensions improves theoretical-experimental agreement.

High RMS roughness amplifies the impact of surface slopes.

Abstract

This paper concentrates on a study where finite conductivity corrections are included in the theoretical description of the effects of roughness on the Casimir force. The roughness data were taken from gold films evaporated onto Silicon and polysterene spheres. We conclude that for a detailed comparison with experimental data, i.e. at the level of at least 5 % at short separations below 200 nm, the lateral dimensions of roughness for real films should be included in the theoretical considerations. Moreover, if the RMS roughness is considerable, high local surface slopes are shown to have a significant effect on the Casimir force.