Feedback control of trapped coherent atomic ensembles

TL;DR

This paper presents a feedback control method for trapped atomic ensembles that uses weak optical measurements and microwave manipulations to protect quantum states from decoherence, enhancing atomic sensor performance.

Contribution

It introduces a novel feedback scheme combining weak optical measurements and microwave control to mitigate collective noise in atomic ensembles.

Findings

Feedback effectively suppresses collective noise effects.

The scheme improves coherence times of atomic superposition states.

Potential to enhance atomic interferometer sensitivity.

Abstract

We demonstrate how to use feedback to control the internal states of trapped coherent ensembles of two-level atoms, and to protect a superposition state against the decoherence induced by a collective noise. Our feedback scheme is based on weak optical measurements with negligible back-action and coherent microwave manipulations. The efficiency of the feedback system is studied for a simple binary noise model and characterized in terms of the trade-off between information retrieval and destructivity from the optical probe. We also demonstrate the correction of more general types of collective noise. This technique can be used for the operation of atomic interferometers beyond the standard Ramsey scheme, opening the way towards improved atomic sensors.