Collisional relaxation in diffuse clouds of trapped bosons - art. no. 053603

The damping of collective modes and the relaxation of temperature anisotrop ies in a trapped Bose gas is determined at temperatures above the Bose-Eins tein condensation temperature in the collisionless regime. We demonstrate f or both cases how the effects of collisions may be treated perturbatively a nd calculate relaxation rates from a variational principle. Our results are compared with experiment and with previous theoretical calculations.