Dynamic depletion in a Bose condensate via a sudden increase of the   scattering length
  We examine the time-dependent quantum depletion of a trapped Bose condensate arising from a rapid increase of the scattering length. Our solution indicates that a significant buildup of incoherent atoms can occur within a characteristic time short compared with the harmonic trap period. We discuss how the depletion density and the characteristic time depend on the physical parameters of the condensate. 
C.K. Law, P.T. Leung and M.C. Chu