Abstract
The general solution of the problem of two two-level atoms with degenerate two-photon transitions interacting with a cavity single-mode radiation field in the presence of the Stark shift terms is obtained. The temporal evolution of the atomic inversion for the single-atom case, the entropy squeezing and the atomic variances squeezing are studied. We use the linear entropy and von Neumann entropy to measure the degree of entanglement between the atoms and the field. It has shown that an increase in the value of the Stark shift parameter leads to an increase in the degree of entanglement. These aspects are sensitive to changes in the Stark shift parameter. (C) 2012 Elsevier B.V. All rights reserved.