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Unitary Cavity Spin Squeezing by Quantum Erasure (1109.3752v2)
Published 17 Sep 2011 in quant-ph
Abstract: Deterministic light-induced spin squeezing in an atomic gas is limited by photon shot noise or, equivalently, by atomic state information escaping with the light field mediating the effective atom-atom interaction. We show theoretically that the performance of cavity spin squeezing [M.H. Schleier-Smith, I.D. Leroux, and V. Vuleti\'{c}, Phys. Rev. A 81, 021804(R) (2010)] can be substantially improved by erasing the light-atom entanglement, and propose several methods for doing so. Accounting for light scattering into free space, quantum erasure improves the scaling of cavity squeezing from S-1/2 to S-2/3, where S is the total atomic spin.