Abstract
In this work, we investigate the effect of the initial phase of the field and the atomic coherence on the time evolution of entropy squeezing of the atom and the atomic inversion in the three-photon Jaynes–Cummings model. Moreover, the evolution of the von Neumann entropy of the atom, Q function and the generation of the Schrödinger-cat states are examined. The results show that the entropy squeezing of the atom and the atomic inversion are sensitive to the initial phase of the field and the initial atomic state. It is also found that the Schrödinger-cat states of the cavity field can be obtained at one half of the revival time in the large photon number approximation.