Kinetic evolution of trapped Bose gas in evaporative cooling

Summary form only given.The successful demonstrations of Bose-Einstein condensation (BEG) with alkali atoms in a magnetic trap have opened up a new field of quantum physics. The evaporative cooling that enables six-order increase of phase space density is the essential technique for achieving the BEC transition in these experiments. However, at low temperatures, this cooling method is strongly affected by Bose statistics of alkali atoms, since evaporation occurs through the scattering process between trapped atoms. The quantum kinetics of nonequilibrium gas has been the subject of considerable interest for classic gas on the basis of truncated Boltzman distribution. We extend this method to treat the quantum statistics.