Scalable Spin Squeezing for Quantum-Enhanced Magnetometry with Bose-Einstein Condensates

TL;DR

This paper demonstrates scalable spin squeezing in Bose-Einstein condensates, enabling quantum-enhanced magnetometry with large atom numbers and achieving significant sensitivity improvements in small probe volumes.

Contribution

It introduces a method to generate large-scale atomic squeezing via non-linear dynamics in BECs, scalable to over 10^7 atoms, and applies it to quantum-enhanced magnetometry.

Findings

Achieved 5.3 dB squeezing for 12,300 atoms.

Predicted scalability to over 10^7 atoms.

Demonstrated quantum-enhanced magnetometry with 310 pT sensitivity.

Abstract

A major challenge in quantum metrology is the generation of entangled states with macroscopic atom number. Here, we demonstrate experimentally that atomic squeezing generated via non-linear dynamics in Bose Einstein condensates, combined with suitable trap geometries, allows scaling to large ensemble sizes. We achieve a suppression of fluctuations by 5.3(5) dB for 12300 particles, which implies that similar squeezing can be achieved for more than 10$^7$ atoms. With this resource, we demonstrate quantum-enhanced magnetometry by swapping the squeezed state to magnetically sensitive hyperfine levels that have negligible nonlinearity. We find a quantum-enhanced single-shot sensitivity of 310(47) pT for static magnetic fields in a probe volume as small as 90 $\mu$m$^3$.