Condensate fluctuations in the dilute Bose gas
Abstract
The fluctuations of a number of particles in the Bose-Einstein condensate are studied in the grand canonical ensemble with an effective single-mode Hamiltonian, which is derived from an assumption that the mode corresponding to the Bose-Einstein condensate does not asymptotically correlate with other modes. The fluctuations are evaluated in the dilute limit with a proposed simple method, which is beyond the mean-field approximation. The accuracy of the latter is estimated; it is shown that the mean-field scheme does not work for the single-mode Hamiltonian, while for the Hartree Hamiltonian it allows us to estimate the condensate fluctuations up to a numerical factor. As a hypothesis, a formula is proposed that relates the fluctuations in the canonical ensemble with that of the grand canonical one.
Keywords
Cite
@article{arxiv.cond-mat/0212221,
title = {Condensate fluctuations in the dilute Bose gas},
author = {Alexander Yu. Cherny},
journal= {arXiv preprint arXiv:cond-mat/0212221},
year = {2007}
}
Comments
8 pages, no figures