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Q: Fachverband Quantenoptik und Photonik

Q 32: Quantengase (Gitter III)

Q 32.6: Talk

Thursday, March 13, 2008, 09:45–10:00, 1C

Mott-insulator states of ultracold atoms in optical resonators — Jonas Larson¹, Sonia Fernandez-Vidal², •Giovanna Morigi², and Maciej Lewenstein¹ — ¹ICFO - Institut de Ciencies Fotoniques, Castelldefels (Barcelona), Spain — ²Departament de Fisica, Universitat Autonoma de Barcelona, 08193 Bellaterra, Spain

We investigate a paradigm example of cavity quantum electrodynamics with many body systems: an ultracold atomic gas inside a pumped optical resonator, confined by the mechanical potential emerging from the cavity-field spatial mode structure. When the optical potential is sufficiently deep, the atomic gas is in the Mott-insulator state as in open space. Inside the cavity, however, the potential depends on the atomic distribution, which determines the refractive index of the medium, thus altering the intracavity-field amplitude. We derive the effective Bose-Hubbard model describing the physics of the system in one dimension and study the crossover between the superfluid -- Mott-insulator quantum states. We predict the existence of overlapping stability regions corresponding to competing insulator-like states. Bistable behavior, controlled by the pump intensity, is encountered in the vicinity of the shifted cavity resonance.