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Q: Quantenoptik

Q 10: Poster: Nonlinear Optics

Q 10.5: Poster

Tuesday, April 3, 2001, 12:30–15:00, AT2

Cooperative Raman-type transitions in the system of two four-level atoms: Entanglement in the spin subsystem of two spatially resolved atomic ensembles — •D.V. Kupriyanov, I.M. Sokolov, and A.V. Slavgorodski — Department of Theoretical Physics, State Technical University, 195251, St.-Petersburg

In the paper we have considered the optical coupling of two four level atoms via the cooperative Raman scattering of the correlated photons of the non-degenerate spontaneous parametric radiation. The Raman scattering of twin photons incident on the atoms is additionally stimulated by coherent classical radiation in such a way, that it is slightly off-resonant for each atom considered independently but resonant for joint system. There have been discussed the special excitation conditions when the amplitude of the cooperative stimulated Raman scattering from quantum to classical modes becomes greater than the normal transition rates associated with independent Raman scattering. In certain conditions the weak entanglement between the Zeeman sublevels in the ground states of these atoms can appear. The small admixture of entanglement in the system of two atoms leads to the strong entanglement between transverse macroscopic spin fluctuations of two spatially resolved atomic ensembles coupled by such quantum light. The proposed mechanism of entanglement is relevant to the ground state spin subsystem of two distant macroscopic and optically thin atomic ensembles. Such an entangled state can be stored for long time and used as a basic EPR system in different applications pursuing the goal to spread the quantum information schemes on atomic subsystems.