Improved constraints on non-Newtonian forces at 10 microns

TL;DR

This paper reports improved experimental constraints on hypothetical non-Newtonian forces at 10 microns, using cryogenic micro-cantilevers, setting the most stringent bounds in the 5-15 micron range.

Contribution

The authors developed an enhanced cryogenic micro-cantilever setup with magnetic calibration, achieving the tightest limits on Yukawa-type deviations at micron scales.

Findings

Set new upper bounds on non-Newtonian forces at 10 microns

Excluded forces with strength |α| > 14,000 at 10 microns

Improved previous constraints by over three times

Abstract

Several recent theories suggest that light moduli or particles in "large" extra dimensions could mediate macroscopic forces exceeding gravitational strength at length scales below a millimeter. Such new forces can be parameterized as a Yukawa-type correction to the Newtonian potential of strength $\alpha$ relative to gravity and range $\lambda$. To extend the search for such new physics we have improved our apparatus utilizing cryogenic micro-cantilevers capable of measuring attonewton forces, which now includes a switchable magnetic force for calibration. Our most recent experimental constraints on Yukawa-type deviations from Newtonian gravity are more than three times as stringent as our previously published results, and represent the best bound in the range of 5 - 15 microns, with a 95 percent confidence exclusion of forces with $|\alpha| > 14,000$ at $\lambda$ = 10 microns.