Test of Equivalence Principle at $10^{-8}$ Level by a Dual-species Double-diffraction Raman Atom Interferometer

TL;DR

This paper presents an improved test of the weak equivalence principle using a dual-species atom interferometer with a novel double-diffraction Raman scheme, achieving a sensitivity of 10^{-8} in measuring gravitational equivalence.

Contribution

It introduces a four-wave double-diffraction Raman transition scheme for dual-species atom interferometry, enhancing noise suppression and measurement precision.

Findings

Measured Eötvös parameter η = (2.8 ± 3.0) × 10^{-8}

Achieved statistical uncertainty of 0.8 × 10^{-8} at 3200 seconds

Identified Coriolis effect as the major source of uncertainty

Abstract

We report an improved test of the weak equivalence principle by using a simultaneous $^{85}$Rb-$^{87}$Rb dual-species atom interferometer. We propose and implement a four-wave double-diffraction Raman transition scheme for the interferometer, and demonstrate its ability in suppressing common-mode phase noise of Raman lasers after their frequencies and intensity ratios are optimized. The statistical uncertainty of the experimental data for E\"{o}tv\"{o}s parameter $\eta$ is $0.8\times10^{-8}$ at 3200 s. With various systematic errors corrected the final value is $\eta=(2.8\pm3.0)\times10^{-8}$. The major uncertainty is attributed to the Coriolis effect.