Evolution of the squeezing character of an initially squeezed EM field in the Dicke model

Abstract The evolution of an initially squeezed electromagnetic (EM) field was studied by using the Dicke model and the perturbation approach. The study covers both one-photon and two-photon interaction between the squeezed field and the cooperative atomic system. The results show that during the early evolution stage in the one-photon Dicke model the nonclassical statistical property (squeezing) gradually decays. But under certain conditions in the two-photon model the squeezing will be enhanced. The physical meaning of these phenomena is discussed.