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Frontiers in Optics

Spin squeezing and cavity-aided nondemolition measurements

Zilong Chen, Justin Bohnet, S. Sankar, Jiayan Dai, Joshua M. Weiner, Kevin C. Cox, James K. Thompson

Published Jan 1, 2012• 0 citations
Publisher

Abstract

Quantum nondemolition measurements are used to prepare an entangled ensemble of nearly 106 atoms with 3.4(6) dB enhancement in spectroscopic sensitivity beyond the standard quantum limit, and may lead to improved quantum sensors.
DOI
10.1364/ls.2012.ltu4j.3

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Probing the collective spin state of an ensemble of atoms may provide a means to reduce heating via the photon recoil associated with the measurement and provide a robust, scalable route for preparing highly entangled states with spectroscopic sensitivity below the standard quantum limit for coherent spin states. The collective probing relies on obtaining a very large optical depth that can be effectively increased by placing the ensemble within an optical cavity such that the probe light passes many times through the ensemble. Here we provide expressions for measurement resolution and spectroscopic enhancement in such cavity-aided nondemolition measurements as a function of the cavity detuning. In particular, fundamental limits on spectroscopic enhancements in 87Rb{}^{87}\mathrm{Rb}87Rb are considered.