A study on quantum discord sudden changes

For open quantum systems, quantum discord sudden changes (QDSCs) may appear in the dynamics instead of sudden death appears in quantum entanglement. In this paper, we study the dynamics of quantum discord and explore the relation between the entanglement sudden death and QDSC. We find that the QDSC is sensitive to the initial states and the excitation number in the total system (the qubits + environment). By using the geometric measurement of the quantum correlation, the geometric interpretation for the QDSC is presented and the condition for the emergence of the QDSC is given. Furthermore, we observe that the entanglement sudden death and QDSC do not have one to one correspondence for open quantum systems.