Anomalous temperature dependence of the Casimir force for thin metal films

TL;DR

This paper predicts a non-monotonous temperature dependence of the Casimir force for thin metal films, showing it can decrease or increase with temperature depending on conditions, which could clarify the role of electron relaxation.

Contribution

It introduces a theoretical prediction of unusual temperature behavior of the Casimir force in thin films using the Drude model, suggesting experimental tests to resolve debates on electron relaxation effects.

Findings

Casimir force decreases with temperature due to conductivity reduction

At high temperatures, the force increases because of thermal radiation pressure

Non-monotonous temperature dependence can be experimentally observed

Abstract

Within the framework of the Drude dispersive model, we predict an unusual non-monotonous temperature dependence of the Casimir force for thin metal films. For certain conditions, this force decreases with temperature due to the decrease of the metallic conductivity, whereas the force increases at high temperatures due to the increase of the thermal radiation pressure. We consider the attraction of a film to: either (i) a bulk ideal metal with a planar boundary, or (ii) a bulk metal sphere (lens). The experimental observation of the predicted non-monotonous temperature dependence of the Casimir force can put an end to the long-standing discussion on the role of the electron relaxation in the Casimir effect.