Saturation effects in experiments on the thermal Casimir effect

TL;DR

This paper investigates three different Casimir effect experiments and demonstrates that saturation effects can explain the discrepancies between theoretical predictions and experimental results.

Contribution

It introduces saturation effects as a unifying explanation for inconsistencies in multiple Casimir force measurements.

Findings

Saturation effects reconcile theory and experiment in metal-metal Casimir force measurements.

Saturation effects account for the unexpected force change in laser-irradiated semiconductor experiments.

Saturation effects explain the smaller-than-expected atom-wall Casimir force change in Bose-Einstein condensate experiments.

Abstract

We address three different problematic Casimir experiments in this work. The first is the classical Casimir force measured between two metal half spaces; here in the form of the Casimir pressure measurement between a gold sphere and a gold plate as performed by Decca et al. [Phys. Rev. D 75, 077101 (2007)]; theory predicts a large negative thermal correction, absent in the high precision experiment. The second experiment is the measurement of the Casimir force between a metal plate and a laser irradiated semiconductor membrane as performed by Chen et al. [Phys. Rev. B 76, 035338 (2007)]; the change in force with laser intensity is larger than predicted by theory. The third experiment is the measurement of the Casimir force between an atom and a wall in the form of the measurement by Obrecht et al. [Phys. Rev. Lett. 98 063201 (2007)] of the change in oscillation frequency of a Rb Bose-Einstein condensate trapped to a fused silica wall; the change is smaller than predicted by theory. We show that saturation effects can explain the discrepancies between theory and experiment observed in all these cases.