Regensburg 2007 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 21: Solids at Low Temperature - Poster Session

TT 21.3: Poster

Mittwoch, 28. März 2007, 14:00–17:45, Poster A

Strongly interacting bose gas in an optical lattice. — •Oleksandr Fialko, Christopher Moseley, and Klaus Ziegler — Institut für Physik, Universität Augsburg, Germany

We study the Bose-Hubbard model, projected onto the regions where two Mott-insulating phases merge. These projections can be described by a hard-core Bose gas which can be treated by locally paired spin-1/2 fermions.

This effective fermion model is analyzed in terms of a mean-field approximation and Gaussian fluctuations. The mean-field solution gives us the phase diagram with the two merging Mott insulators and an intermediate superfluid. The effect of quantum and thermal fluctuations are investigated. In particular, we study the role of gapless and gapped modes in the fluctuations, and calculate the static structure factor.