Enhancement and suppression of spontaneous emission and light scattering   by quantum degeneracy
  Quantum degeneracy modifies light scattering and spontaneous emission. For fermions, Pauli blocking leads to a suppression of both processes. In contrast, in a weakly interacting Bose-Einstein condensate, we find spontaneous emission to be enhanced, while light scattering is suppressed. This difference is attributed to many-body effects and quantum interference in a Bose-Einstein condensate. 
A. Gorlitz and A. P. Chikkatur and W. Ketterle