Classical correlation and quantum discord mediated by cavity in two coupled qubits

We study the dynamics of classical correlation and quantum discord of two coupled two-level atoms interacting with a cavity initially in vacuum, coherent and thermal equilibrium states, respectively. The interplay between the atom-atom coupling and mean number of photons is considered. We find that, for a cavity in a vacuum state, classical correlation or quantum discord shows a sudden change in behaviour during the evolution, and evolves periodically for zero and very large qubit-qubit couplings. However, for coherent and thermal equilibrium states, the classical correlation and quantum discord present the phenomenon of collapse-revival when the qubit-qubit coupling is much greater than the mean number of photons. The period of collapse-revival becomes long as the qubit-qubit coupling and mean number of photons increase. The relationship between quantum discord and entanglement in the studied system is considered.