Kinetic energy of uniform Bose-Einstein condensate
  The Bogoliubov theory of a uniform weakly-nonideal Bose-Einstein condensate leads to a divergent expression for the kinetic energy of atoms. However, the latter can be determined provided that the dependence of the scattering length on atomic mass is known. The explicit expressions are derived for the kinetic energy through parameters that specify interatomic interaction. The kinetic energy of condensate atoms noticeably exceeds the total energy. Numerical data are presented for Rb-87 and Na-23 condensates. 
E. E. Nikitin, L. P. Pitaevskii