No anomalous scaling in electrostatic calibrations for Casimir force measurements

TL;DR

This paper demonstrates that proper electrostatic calibrations in Casimir force experiments follow expected scaling laws, contradicting previous reports of anomalies, and shows that voltage dependencies do not imply anomalous behavior.

Contribution

The study provides experimental evidence that electrostatic scaling laws are consistent with classical electrostatics, clarifying misconceptions from prior anomalous findings.

Findings

Electrostatic scaling law aligns with elementary electrostatics.

Voltage minimizing the force depends on separation but does not indicate anomalies.

Previous reported anomalies are not observed under proper calibration conditions.

Abstract

In a recent paper (Phys.Rev.A78, 020101(R) (2008)), Kim at al. have reported a large anomaly in the scaling law of the electrostatic interaction between a sphere and a plate, which was observed during the calibration of their Casimir force set-up. Here we experimentally demonstrate that in proper electrostatic calibrations the scaling law follows the behavior expected from elementary electrostatic arguments, even when the electrostatic voltage that one must apply to minimize the force (typically ascribed to contact potentials) depends on the separation between the surfaces.