Biparabolic model of periodic field for Bose-Einstein condensation of ideal gas in laser field of counterpropagating waves

The phenomenon of the ideal gas Bose-Einstein condensation in the field of periodic potential formed by counterpropagating laser waves is investigated. The biparabolic approximation is used for calculations. By means of this method we calculate the total number of trapped atoms in the potential, the number of atoms in each energy zone, the number of condensed and non condensed atoms. The key result is that the critical temperature of condensation and the number of condensed atoms decrease slowly with the increasing depth of the potential. All numerical calculations are made for the optical transition 3S1/2 - 3P3/2 of sodium atoms