Near equilibrium, the rate of relaxation to equilibrium and the transport
properties of excitations (bogolons) in a dilute Bose-Einstein condensate (BEC)
are determined by three collision integrals, G12,
G22, and G31. All three collision integrals
conserve momentum and energy during bogolon collisions, but only G22 conserves bogolon number. Previous works have considered the
contribution of only two collision integrals, G22 and G12. In this work, we show that the third collision integral G31 makes a significant contribution to the bogolon number
relaxation rate and needs to be retained when computing relaxation properties
of the BEC. We provide values of relaxation rates in a form that can be applied
to a variety of dilute Bose-Einstein condensates.Comment: 18 pages, 4 figures, accepted by Journal of Low Temperature Physics
7/201