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arXiv · 1007.1814

A Comparison of the Attempts of Quantum Discord and Quantum Entanglement to Capture Quantum Correlations

Asma Al-Qasimi·Daniel F. V. James
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Abstract

Measurements of Quantum Systems disturb their states. To quantify this non-classical characteristic, Zurek and Ollivier introduced the quantum discord, a quantum correlation which can be nonzero even when entanglement in the system is zero. Discord has aroused great interest as a resource that is more robust against the effects of decoherence and offers exponential speed up of certain computational algorithms. Here, we study general two-level bipartite systems and give general results on the relationship between discord, entanglement, and linear entropy, and identify the states for which discord takes a maximal value for a given entropy or entanglement, thus placing strong bounds on entanglement-discord and entropy-discord relations. We find out that although discord and entanglement are identical for pure states, they differ when generalized to mixed states as a result of the difference in the method of generalization.

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Asma Al-Qasimi, Daniel F. V. James. 2010-07-12. A Comparison of the Attempts of Quantum Discord and Quantum Entanglement to Capture Quantum Correlations. https://arxiv.org/abs/1007.1814

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