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Q: Fachverband Quantenoptik und Photonik

Q 70: Quantum Gases: Bosons VI

Q 70.5: Vortrag

Freitag, 4. März 2016, 15:30–15:45, f342

Phase diagrams of ultra cold selforganized structures in cavity QED potentials — •Astrid Elisa Niederle, Heiko Rieger, and Giovanna Morigi — Theoretische Physik, Universität des Saarlandes, D-66123 Saarbrücken, Germany

Scattering of photons into an optical resonator by laser-driven atoms can give rise to atomic structures, which emerge from the interplay between drive and cavity losses. These structures match an underlying Bragg order, thus maximizing the number of intracavity photons which in turn mechanically stabilize the atomic density distribution. We analyse the phases of bosonic atoms confined on a plane by an external optical lattice, whose periodicity is commensurate and incommensurate with the wavelenght of a cavity mode. This system can be described by a Bose-Hubbard model with a specific dynamical on-site potential [1]. We determine the ground state properties using local mean field theory complemented by a cluster analysis [2]. We identify the parameter regimes for which this underlying order emerges and show that it can exhibit nontrivial features, to which quantitatively different patterns correspond. In the incommensurate case these phases are all compressible, and for given atomic densities can exhibit superfluidity even at vanishing tunneling. We discuss the corresponding observables and show that these predictions could be tested in existing experiments [3].

[1] Phys. Rev. A 81 (2010) 043407 and Phys. Rev. A 88 (2013) 043618, [2] New. J. Physics 15 (2013) 075029, [3] Nautre 464 (2010) 1301