Gravitational Experiment Below 1 Millimeter and Comment on Shielded Casimir Backgrounds for Experiments in the Micron Regime

TL;DR

This paper reports on an experimental test for gravitational forces below 1 mm using oscillators and shielding, finding no evidence for new forces and discussing shielding techniques to reduce Casimir backgrounds in micron-scale experiments.

Contribution

It introduces a novel shielding approach to suppress backgrounds in short-range gravity experiments and evaluates its potential for future sub-micron tests.

Findings

No new forces detected between 75 microns and 1 mm

Sensitivity reached about 1000 times gravitational strength

Shielding techniques could reduce Casimir backgrounds in micron experiments

Abstract

We present the status of an experimental test for gravitational strength forces below 1 mm. Our experiment uses small 1 kilohertz oscillators as test masses, with a stiff counducting shield between them to suppress backgrounds. At the present sensitivity of approximately 1000 times gravitational strength, we see no evidence for new forces with interaction ranges between 75 microns and 1 mm. While the Casimir background is not expected to be significant at this range, an extension of the shielding technique we employ may be useful for reducing this background in experiments below a few microns. We describe a possible implementation.