The Budapest Quantum Optics Group

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Interacting bosons in an optical cavity

Dandan Su

(Institut für Theoretische Physik Johann Wolfgang Goethe-Universität)

Time: Mon Sep 1 10:00:00 2014
Location: Building 1, Room 123

We numerically simulate strongly correlated ultracold bosons coupled to a high-finesse optical cavity. Assuming that a weak classical optical lattice is added in the cavity direction, we describe this system by a generalized Bose-Hubbard model, which is solved by means of bosonic dynamical mean-field theory. For a single-mode cavity, pumped by a laser beam in the transverse direction, the complete phase diagram is established, which contains two novel self-organized quantum phases, lattice supersolid and checkerboard solid, in addition to conventional phases such as superfluid and Mott insulator.[1] At finite but low temperature, thermal fluctuations are found to enhance the buildup of these self-organized phases. We demonstrate that cavity-mediated long-range interactions can give rise to stable lattice supersolid and checkerboard solid phases even in the regime of strong s-wave scattering. In the presence of a harmonic trap, we discuss the coexistence of these self-organized phases, as relevant to experiments. Furthermore, we investigate a system of bosons coupled to two crossed cavity modes, whose axes’ angle is 60 degree. We study self-organization phenomena in the resulting hexagonal lattice.