Density correlations in ultracold atomic Fermi gases
Abstract
We investigate density fluctuations in a coherent ensemble of interacting fermionic atoms. Adapting the concept of full counting statistics, well-known from quantum optics and mesoscopic electron transport, we study second-order as well as higher-order correlators of density fluctuations. Using the mean-field BCS state to describe the whole interval between the BCS limit and the BEC limit, we obtain an exact expression for the cumulant-generating function of the density fluctuations of an atomic cloud. In the two-dimensional case, we obtain a closed analytical expression. Poissonian fluctuations of a molecular condensate on the BEC side are strongly suppressed on the BCS side. The size of the fluctuations in the BCS limit is a direct measure of the pairing potential. We also discuss the BEC-BCS crossover of the third cumulant and the temperature dependence of the second cumulant.
Keywords
Cite
@article{arxiv.cond-mat/0412269,
title = {Density correlations in ultracold atomic Fermi gases},
author = {W. Belzig and C. Schroll and C. Bruder},
journal= {arXiv preprint arXiv:cond-mat/0412269},
year = {2022}
}
Comments
4 pages, 4 figures. To appear in Phys. Rev. A. New calculation of the bin statistics of a free Bose gas; updated and extended bibliography