Spatially Homogeneous Entanglement for Matter-Wave Interferometry Created with Time-Averaged Measurements

TL;DR

This paper presents a method to produce spatially homogeneous entangled states of atoms using time-averaged measurements, enabling robust spin squeezing for matter-wave interferometry and free-space quantum sensors.

Contribution

It introduces a technique employing time averaging in collective measurements to generate spatially homogeneous entangled states with significant spin squeezing.

Findings

Achieved 11(1) dB of spin squeezing.

Demonstrated robustness of squeezing after atom release.

Reduced effects of spatial inhomogeneity in measurements.

Abstract

We demonstrate a method to generate spatially homogeneous entangled, spin-squeezed states of atoms appropriate for maintaining a large amount of squeezing even after release into the arm of a matter-wave interferometer or other free space quantum sensor. Using an effective intracavity dipole trap, we allow atoms to move along the cavity axis and time average their coupling to the standing wave used to generate entanglement via collective measurements, demonstrating 11(1) dB of directly observed spin squeezing. Our results show that time averaging in collective measurements can greatly reduce the impact of spatially inhomogeneous coupling to the measurement apparatus.