Atomic four-wave mixing: fermions versus bosons
  We compare the efficiency of four-wave mixing in quantum degenerate gases of bosonic and fermionic atoms. It is shown that matter-wave gratings formed from either bosonic or fermionic atoms can in principle exhibit nearly identical Bragg-scattering, i.e. four-wave mixing, properties. This implies that effects such as coherent matter-wave amplification and superradiance can occur in degenerate fermi gases. While in the boson case the Bragg resonance is clearly due to `Bose enhancement', in the case of fermions the resonance is due to constructive many-particle quantum interference. 
M. G. Moore and Pierre Meystre