Anomalies in electrostatic calibrations for the measurement of the Casimir force in a sphere-plane geometry

TL;DR

This paper reports on unexpected anomalies in electrostatic calibrations used for measuring the Casimir force, highlighting potential inaccuracies in previous experiments and suggesting the need for reanalysis.

Contribution

It provides the first detailed analysis of anomalous electrostatic behavior in sphere-plane geometries affecting Casimir force measurements.

Findings

Electrostatic signal scaling exponent is smaller than Coulomb prediction.

Residual potential varies with distance.

Anomalies may impact the accuracy of Casimir force measurements.

Abstract

We have performed precision electrostatic calibrations in the sphere-plane geometry and observed anomalous behavior. Namely, the scaling exponent of the electrostatic signal with distance was found to be smaller than expected on the basis of the pure Coulombian contribution and the residual potential found to be distance dependent. We argue that these findings affect the accuracy of the electrostatic calibrations and invite reanalysis of previous determinations of the Casimir force.