  Momentum distributions and temporal power spectra of nonzero temperature
Bose-Einstein condensates are calculated using a Gross-Pitaevskii model. The
distributions are obtained for micro-canonical ensembles (conservative
Gross-Pitaevskii equation) and for grand-canonical ensembles (Gross-Pitaevskii
equation with fluctuations and dissipation terms). Use is made of an
equivalence between statistics of the solutions of conservative
Gross-Pitaevskii and dissipative complex Ginzburg-Landau equations. In all
cases the occupation numbers of modes follow a k^(-2) dependence, which
corresponds in the long wavelength limit (k->0) to Bose-Einstein distributions.
The temporal power spectra are of f^(-a) form, where: a=2-D/2 with D the
dimension of space.
