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arXiv · 2210.00096

Quantum Discord and Logarithmic Negativity in the Generalized n-qubit Werner State

M. S. Ramkarthik·Devvrat Tiwari·Pranay Barkataki
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Abstract

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 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 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.

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M. S. Ramkarthik, Devvrat Tiwari, Pranay Barkataki. 2022-09-30. Quantum Discord and Logarithmic Negativity in the Generalized n-qubit Werner State. https://doi.org/10.1007/s10773-020-04663-2

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