Quantum discord and logarithmic negativity in the generalized \(n\)-qubit Werner state. (English) Zbl 1462.81040
Summary: Quantum Discord (QD) is a measure of the total quantum non-local correlations of a quantum system. The formalism of quantum discord has been applied to various two-qubit mixed states and it has been reported that there is a non-zero quantum discord even when the states are unentangled. To this end, we have calculated the Quantum Discord for a higher than two qubit mixed state, that is, the generalized \(n\)-qubit Werner state with a bipartite split. We found that the QD saturates to a straight line with a unit slope in the thermodynamic limit. Qualitative studies of entanglement between the two subsystems using logarithmic negativity revealed that the entanglement content between them increases non-uniformly with the number of qubits leading to its saturation. We have proved the above claims both analytically and numerically.
MSC:
| 81P43 | Quantum discord |
| 81P42 | Entanglement measures, concurrencies, separability criteria |
| 81P40 | Quantum coherence, entanglement, quantum correlations |
| 81P16 | Quantum state spaces, operational and probabilistic concepts |
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