Low dimensional Bose gases
Abstract
We present an improved manybody Tmatrix theory for partially BoseEinstein condensed atomic gases by treating the phase fluctuations exactly. The resulting meanfield theory is valid in arbitrary dimensions and able to describe the lowtemperature crossover between three, two, and onedimensional Bose gases. When applied to a degenerate twodimensional atomic hydrogen gas, we obtain a reduction of the threebody recombination rate, which compares favorably with experiment. Supplementing the meanfield theory with a renormalizationgroup approach to treat the critical fluctuations, we also incorporate into the theory the KosterlitzThouless transition that occurs in a homogeneous Bose gas in two dimensions. In particular, we calculate the critical conditions for the KosterlitzThouless phase transition as a function of the microscopic parameters of the theory. The proposed theory is further applied to a trapped onedimensional Bose gas, where we find good agreement with exact numerical results obtained by solving a nonlinear Langevin field equation.
 Publication:

Physical Review A
 Pub Date:
 July 2002
 DOI:
 10.1103/PhysRevA.66.013615
 arXiv:
 arXiv:condmat/0202085
 Bibcode:
 2002PhRvA..66a3615A
 Keywords:

 03.75.Fi;
 67.40.w;
 32.80.Pj;
 Boson degeneracy and superfluidity of <sup>4</sup>He;
 Optical cooling of atoms;
 trapping;
 Condensed Matter
 EPrint:
 14 pages, 13 figures, revtex