Heidelberg 2015 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 5: Quantum Gases: Bosons I
Q 5.4: Vortrag
Montag, 23. März 2015, 12:15–12:30, P/H2
Effect of cavity-mediated long-range interactions on the Mott insulator- superfluid transition — •Nishant Dogra1, Ferdinand Brennecke2, Rafael Mottl1, Lorenz Hruby1, Renate Landig1, Sebastian Huber3, Tobias Donner1, and Tilman Esslinger1 — 1HPF D4, Quantum Optics Group, Institute for Quantum Electronics, ETH Zurich,Otto-Stern-Weg-1,Zurich-8093, Swizerland — 2Physikalisches Institut, Universität Bonn, Wegelerstrasse 8, Bonn-53115 — 3HIT K 23.4, Institute for Theoretical Physics, ETH Zurich, Wolfgang-Pauli-Strasse 27, Zurich-8093
The transversal illumination of a strongly coupled BEC-cavity system by a laser field leads to a phase transition from a superfluid to a supersolid phase due to the competition between the kinetic energy and the cavity-mediated long-range interactions. We theoretically study the effect of a 3D classical optical lattice on this system which enhances the strength of the short-range interactions and hence introduces another competing energy scale. This system can be mapped to an extended Bose-Hubbard model. In the limit where the classical lattice is commensurate with the cavity generated dynamical lattice, we solve this system using different mean-field approaches. Besides the Mott-insulator and the superfluid phases exhibited by the Bose-Hubbard model, the cavity-mediated long-range interactions give rise to a charge density wave insulator and a supersolid phase. We also calculate the excitation spectrum of the different phases and relate it to the nature of the transition between them. We further briefly discuss the status of the experimental implementation of this scheme.