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arXiv · 1110.4498

Dynamic density-density correlations in interacting Bose gases on optical lattices

S. Ejima·H. Fehske·F. Gebhard
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Abstract

In order to identify possible experimental signatures of the superfluid to Mott-insulator quantum phase transition we calculate the charge structure factor $S(k,\omega)$ for the one-dimensional Bose-Hubbard model using the dynamical density-matrix renormalisation group (DDMRG) technique. Particularly we analyse the behaviour of $S(k, \omega)$ by varying---at zero temperature---the Coulomb interaction strength within the first Mott lobe. For strong interactions, in the Mott-insulator phase, we demonstrate that the DDMRG results are well reproduced by a strong-coupling expansion, just as the quasi-particle dispersion. In the superfluid phase we determine the linear excitation spectrum near $k=0$ and compare the DDMRG data with results from mean-field theory.

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S. Ejima, H. Fehske, F. Gebhard. 2011-10-20. Dynamic density-density correlations in interacting Bose gases on optical lattices. https://doi.org/10.1088/1742-6596/391/1/012143

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