Atom-light entanglement for precise field sensing in the optical domain

TL;DR

This paper discusses a protocol leveraging strong atom-light interactions in cavity QED systems to enhance electric field sensing precision, achieving significant metrological gain over standard limits.

Contribution

It provides an in-depth analysis of a protocol for quantum-enhanced electric field sensing using atom-light entanglement, including conditions for optimal performance considering decoherence.

Findings

Achieves 10-20 dB metrological gain over standard quantum limit.

Validates protocol robustness through analytical and numerical methods.

Identifies conditions for implementation in cavity QED and ion trap systems.

Abstract

Macroscopic arrays of cold atoms trapped in optical cavities can reach the strong atom-light collective coupling regime thanks to the simultaneous interactions of the cavity mode with the atomic ensemble. In a recent work we reported a protocol that takes advantage of the strong and collective atom-light interactions in cavity QED systems for precise electric field sensing in the optical domain. We showed that it can provide between $10$-$20$~dB of metrological gain over the standard quantum limit in current cavity QED experiments operating with long-lived alkaline-earth atoms. Here, we give a more in depth discussion of the protocol using both exact analytical calculations and numerical simulations, and describe the precise conditions under which the predicted enhancement holds after thoroughly accounting for both photon loss and spontaneous emission, natural decoherence mechanisms in current experiments. The analysis presented here not only serves to benchmark the protocol and its utility in cavity QED arrays but also sets the conditions required for its applicability in other experimental platforms such as arrays of trapped ions.