Seminarium Optyczne

We theoretically investigate the entangled states of an atomic ensemblethat can be obtained via cavity-feedback, varying the atom-lightcoupling from weak to strong, and including a systematic treatment ofdecoherence. In the strong coupling regime for small atomic ensembles, the system is driven by cavity losses into a long-lived, highly-entangled many-body state that we charaterize analytically. In the weak coupling regime for large ensembles, we and analytically the maximum spin squeezing that can be achieved by optimizing both the coupling and the atom number. This squeezing is fundamentally limited by spontaneous emission to a constant value, independent of the atom number.