Excess noise depletion of a Bose-Einstein condensate in an optical   cavity
  Quantum fluctuations of a cavity field coupled into the motion of ultracold bosons can be strongly amplified by a mechanism analogous to the Petermann excess noise factor in lasers with unstable cavities. For a Bose-Einstein condensate in a stable optical resonator, the excess noise effect amounts to a significant depletion on long timescales. 
G. Szirmai, D. Nagy, P. Domokos