Cavity Dynamical Casimir Effect in the presence of a three-level atom
  We consider the scenario in which a damped three-level atom in the ladder or V configurations is coupled to a single cavity mode whose vacuum state is amplified by dint of the dynamical Casimir effect. We obtain approximate analytical expressions and exact numerical results for the time-dependent probabilities, demonstrating that the presence of the third level modifies the photon statistics and its population can serve as a witness of photon generation from vacuum. 
A. V. Dodonov and V. V. Dodonov
quant-ph cond-mat.supr-con