Three-wave mixing of Bogoliubov quasi-particles in a Bose condensate
  A dressed basis is used to calculate the dynamics of three-wave mixing between Bogoliubov quasi-particles in a Bose condensate. Due to the observed oscillations between different momenta modes, an energy splitting, analogous to the optical Mollow triplet, appears in the Beliaev damping spectrum of the excitations from the oscillating modes. 
R. Ozeri, N. Katz, J. Steinhauer and N. Davidson