Entanglement sudden death and influence of the dynamical Stark shift for two Tavis-Cummings atoms

The time dependence of the entanglement for two Tavis-Cummings atoms with dynamical Stark shift is studied. It is shown that the influence of the dynamical Stark shift is not equivalent for different Bell states. Namely for the states ϕ=12(|00〉±|11〉) sudden death of entanglement happens, while for the states ψ=12(|01〉±|10〉) we still have a rest of entanglement. A direct relation between the sudden death of entanglement and the values of the dynamical Stark shift is shown. The fidelity of the system is evaluated.