Dynamics of impurity, local and non-local information for two non   identical qubits
  From the separability point of view the problem of two atoms interact with a single cavity mode is investigated. The density matrix is calculated and used to discuss the entanglement and to examine the dynamics of the local and non-local information. Our examination concentrated on the variation in the mean photon number and the ratio of the coupling parameters. Furthermore, we have also assumed that the atomic system is initially in the ground states as well as in the intermediate states. It has been shown that the local information is transferred to non-local information when the impurity of one qubit or both is maximum. 
N. Metwally, M. Abdel-Aty and M.Sebawe Abdall