Kinetics of Bose-Einstein Condensation in a Trap

The formation process of a Bose-Einstein condensate in a trap is described using a master equation based on quantum kinetic theory, which can be well approximated by a description using only the condensate mode in interaction with a thermalized bath of noncondensate atoms. A rate equation of the form ṅ  =  2W⁺(n)[(1-e^{μ_n-μ}/kT)n+1] is derived, in which the difference between the condensate chemical potential μ_n and the bath chemical potential μ gives the essential behavior. Solutions of this equation give a characteristic latency period for condensate formation and appear to be consistent with the observed behavior of both rubidium and sodium condensate formation.