Occupation number and fluctuations in the finite-temperature Bose-Hubbard model
Abstract
We study the occupation numbers and number fluctuations of ultra-cold atoms in deep optical lattices for finite temperatures within the Bose-Hubbard model. Simple analytical expressions for the mean occupation number and number fluctuations are obtained in the weak-hopping regime using an interpolation between results from different perturbation approaches in the Mott-insulator and superfluid phases. These analytical results are compared to exact one dimensional numerical calculations using a finite temperature variant of the Density-Matrix Renormalisation Group (DMRG) method and found to have a high degree of accuracy. We also find very good agreement in the crossover ``thermal'' region. With the present approach the magnitude of number fluctuations under realistic experimental conditions can be estimated and the properties of the finite temperature phase diagram can be studied.
Keywords
Cite
@article{arxiv.cond-mat/0309587,
title = {Occupation number and fluctuations in the finite-temperature Bose-Hubbard model},
author = {L. I. Plimak and M. Fleischhauer and M. K. Olsen},
journal= {arXiv preprint arXiv:cond-mat/0309587},
year = {2009}
}
Comments
4 pages, 1 eps figure, submitted to PRA