Testing Gravity with Cold-Atom Interferometers

TL;DR

This paper introduces a horizontal cold-atom interferometer gravity gradiometer with high sensitivity, demonstrating a precise measurement of the gravitational constant and setting constraints on hypothetical fifth forces, with potential for further improvements.

Contribution

The work presents a novel horizontal atom interferometer design with suppressed noise, achieving high sensitivity and providing new constraints on gravity and fifth-force parameters.

Findings

Achieved a differential acceleration sensitivity of 4.2×10⁻⁹g/√Hz over 70 cm

Measured the gravitational constant with 3×10⁻⁴ precision

Set statistical constraints on Yukawa-type fifth forces near 10 cm scale

Abstract

We present a horizontal gravity gradiometer atom interferometer for precision gravitational tests. The horizontal configuration is superior for maximizing the inertial signal in the atom interferometer from a nearby proof mass. In our device, we have suppressed spurious noise associated with the horizonal configuration to achieve a differential acceleration sensitivity of 4.2$\times10^{-9}g/\sqrt{Hz}$ over a 70 cm baseline or 3.0$\times10^{-9}g/\sqrt{Hz}$ inferred per accelerometer. Using the performance of this instrument, we characterize the results of possible future gravitational tests. We complete a proof-of-concept measurement of the gravitational constant with a precision of 3$\times10^{-4}$ that is competitive with the present limit of 1.2$\times10^{-4}$ using other techniques. From this measurement, we provide a statistical constraint on a Yukawa-type fifth force at 8$\times$10$^{-3}$ near the poorly known length scale of 10 cm. Limits approaching 10$^{-5}$ appear feasible. We discuss improvements that can enable uncertainties falling well below 10$^{-5}$ for both experiments.