Entanglement in a system of two two-level atoms interacting with a single-mode field

We investigate the entanglement in a system of two coupling atomsinteracting with a single-mode fieldby means of quantum information entropy theory.The quantum entanglement between the two atoms and the coherent field is discussed by usingthe quantum reduced entropy,and the entanglement between the two coupling atoms is also investigatedby using the quantum relative entropy.In addition, the influences of the atomic dipole--dipole interactionintensity andthe average photon number of the coherent field on the degree of the entanglement is examined.The results show that the evolution of the degree of entanglement between the two atomsand the field is just opposite to that of the degree of entanglement between the two atoms.And the properties of the quantum entanglement in the system rely on theatomic dipole--dipoleinteraction and the average photon number of the coherent field.