Berlin 2014 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 42: Quantum gases: Disorder- or interaction-induced effects

Q 42.2: Talk

Thursday, March 20, 2014, 14:30–14:45, UDL HS2002

Phonon-mediated interaction of slow-light polaritons in a BEC — •Hanna-Lena Haug and Michael Fleischhauer — Department of Physics and research center OPTIMAS, University of Kaiserslautern, Germany

We study the dynamics of dark-state polaritons (DSP) in a Bose-Einstein condensate. DSPs are formed in an atomic ensemble interacting in a Λ-type configuration with two light fields under conditions of electromagnetically induced transparency. We consider a BEC of ground-state atoms which interact with the meta-stable spin-state of the Λ-System. This gives rise to an effective interaction between the DSPs, mediated by the Bogoliubov phonons of the BEC as well as to a dissipative mechanism. We analyze how the momentum distribution of the DSPs is modified by this interaction and show that it provides a mechanism for cooling DSPs. We find that the effective mass of the DSPs in the BEC increases, indicating a formation of polarons. Moreover we discuss how the phonon-mediated scattering between two DSPs can be used to create a phase gate for photons. Our analysis shows that a phase shift of π can be realized with our protocol using current experimental technology.