Quantifying Quantumness with Sudden Birth or Death of Entanglement for Two-Qubits System

Quantumness of the correlations between two qubits, coupled to a cavity field whenever the system is open or closed, is investigated when sudden death (or birth) of the entanglement occurs. It is found that quantum correlation not exists only in the entangled state. It's found that the dephasing parameters and the purity of the initial states play an important role in the dynamics behaviors of the quantum correlations, including entanglement. Quantumness of the correlations and entanglement, due to dephasing of the cavity, are damped until the same their values which are contained in their initial states.