Abstract
Starting from the interaction between a 3-level atom in the cascade configuration with an SU(1, 1) quantum system, an effective Hamiltonian for a 2-level atom with the presence of a Stark shift structure is obtained under large detuning and adiabatic elimination. The evolution operator for the new system is obtained and expectation values for different dynamical observables are obtained taking the initial state of the SU(1, 1) system to be a Perelomov coherent state and a superposition state for the 2-level atom. Atomic inversion, atomic variable squeezing and degree of entanglement are investigated for various values of the involved parameters. The effect of the Stark shift parameters is displayed in these phenomena.