Berlin 2008 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 15: Controlling Dirty Bosons: Disorder Effects on BECs
DY 15.2: Vortrag
Dienstag, 26. Februar 2008, 14:45–15:00, MA 001
Ultracold bosons in lattices with disorder created by "heavy" impurities — Konstantin V. Krutitsky1, Michael Thorwart2, Reinhold Egger2, and •Robert Graham1 — 1Fachbereich Physik, Universität Duisburg-Essen, Lotharstraße 1, 47048 Duisburg, Germany — 2Institut für Theoretische Physik IV, Heinrich-Heine-Universität Düsseldorf, Germany
Quantum phases of ultracold bosons with repulsive interactions in optical lattices in the presence of disorder are investigated. The disorder is assumed to be caused by the interaction of the bosons with impurity atoms having a large effective mass. The system is described by the Bose-Hubbard Hamiltonian with on-site energies which have a discrete probability distribution. The phase diagram at zero temperature is calculated using several methods like a strong-coupling expansion, an exact numerical diagonalization, a Bose-Fermi mapping, as well as two different versions of a mean-field theory.