Regensburg 2007 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 25: Quantum Liquids, Bose-Einstein Condensates, Ultracold Atoms, ...

TT 25.3: Vortrag

Donnerstag, 29. März 2007, 14:30–14:45, H18

Dynamical mean-field theory for the Bose-Hubbard model — •Krzysztof Byczuk and Dieter Vollhardt — Theoretical Physics III, Center for Electronic Correlations and Magnetism, Institute for Physics, University of Augsburg, D-86135 Augsburg, Germany

The Bose-Hubbard model and Bose-Einstein condensation are investigated on an infinite dimensional lattice. A new way of rescaling the hopping amplitudes is introduced. This leads to a comprehensive theory which is exactly solvable in the limit of infinite dimensions. The solution is given by dynamical mean-field type equations for normal bosons plus an integro-differential Gross-Pitaevski type equation for superfluid bosons coupled to the normal component by dynamical hybridization functions. Local temporal correlations in the normal and superfluid components are treated exactly whereas spatial correlations are absent. All known limiting cases (free gas, atomic limit, Bogoliubov, Bogoliubov-Hartree, and Popov theories) are recovered. Possible strategies to solve this dynamical mean-field theory for correlated bosons are discussed.