Dynamics of Entanglement and Nonclassical Correlation for Four-Qubit GHZ State

Abstract: Many-qubit entanglement is crucial for quantum information processing although its exploitation is hindered by the detrimental effects of the environment surrounding the many-qubit system. It is thus of importance to study the dynamics of general multipartite nonclassical correlation, including but not restricted to entanglement, under noise. We did this study for four-qubit GHZ state under most common noises in an experiment and found that nonclassical correlation is more robust than entanglement except when it is imposed to dephasing channel. Quantum discord presents a sudden transition in its dynamics for Pauli-X and Pauli-Y noises as well as Bell-diagonal states interacting with dephasing reservoirs and it decays monotonically for Pauli-Z and isotropic noises.