Hannover 2013 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 66: Quantum effects: Entanglement and decoherence II
Q 66.5: Talk
Friday, March 22, 2013, 15:15–15:30, A 310
Dissipative Preparation of Spin Squeezed Atomic Ensembles in a Steady State — •Johannes Otterbach1, Emanuele Dalla Torre1, Eugene Demler1, Vladan Vuletic2, and Mikhail Lukin1 — 1Physics Department, Harvard University — 2Physics Department, Massachussetts Institute of Technology
Spin squeezed states have attracted substantial interest over the last decades from fundamental and application points of view to study many-body entanglement and improve high-precision spectroscopy. One limiting factor for squeezing is the coupling to the environment which usually has detrimental effects on the generation and entanglement fidelity of these states. Here we present a scheme for the deterministic generation of spin squeezed states in coherently driven atomic ensemble of effective spin-1/2 particles collectively interacting with a strongly decaying cavity mode, thus turning dissipation into a resource for entanglement. We show that there exists a dark-state of the cavity dissipation exhibiting squeezing bounded only by the Heisenberg limit and calculate the timescale to reach this state. Upon taking spontaneous atomic scattering into account we find that the steady state is unique and independent of the initial state, and thus squeezing is generated by optical pumping. Finally we determine the general scaling of the squeezing as a function of the single-atom cooperativity and the number of atoms.