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arXiv · 1110.6681

On the optimal measurement for quantum discord of two-qubit states

Mingjun Shi·Chunxiao Sun·Fengjian Jiang·Xinhu Yan·Jiangfeng Du
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Abstract

We present an efficient method to solve the quantum discord of two-qubit X states exactly. A geometric picture is used to clarify whether and when the general POVM measurement is superior to von Neumann measurement. We show that either the von Neumann measurement or the three-element POVM measurement is optimal, and more interestingly, in the latter case the components of the postmeasurement ensemble are invariant for a class of states.

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Mingjun Shi, Chunxiao Sun, Fengjian Jiang, Xinhu Yan, Jiangfeng Du. 2011-10-31. On the optimal measurement for quantum discord of two-qubit states. https://doi.org/10.1103/physreva.85.064104

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