Theory of a spatially periodic Bose condensate in the weakly nonideal Bosegas model

The possibility of constructing the theory of a spatially periodic Bose con densate in the weakly nonideal Bose gas model is studied. The concept of qu asi means and the related separated Bose condensate method are used to deri ve equations for determining the spatially periodic order parameter for zer o temperature at which the contribution of quasiparticles to the thermodyna mics of the bosom system can be neglected. One-period solutions of these eq uations are found. Questions of thermodynamic stability are considered for a spatially periodic Bose condensate.