Effects of Different Time-Dependent Couplings on Two-Atom Entanglement

The effects of different time-independent and time-dependent couplings on two-atom entanglement are studied. The results show that the effects depend on the initial state. For the initial state |ee0〉, it is found that different time-independent couplings make the case without entanglement exhibit entanglement, and time-dependent couplings turn the irregular entanglement regions into regular one. Under the case of decay, for the initial state |eg0〉, the different time-dependent couplings have disbenefit.