Dynamics of quantum correlation and entanglement in a two-qubit system under Dzyaloshinskii-Moriya interaction

We consider a two-qubit system in Werner state. We let it evolve in Heisenberg XY model with Dzyaloshinskii-Moriya interaction. We evaluate concurrence and quantum discord as a measure of entanglement and quantum correlation respectively, thus comparing them. It is shown that quantum correlation is more robust than entanglement. For instance there are situations where entanglement may vanishe, whereas we may still have quantum correlation.