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

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 نشر من قبل Mingjun Shi
 تاريخ النشر 2011
  مجال البحث فيزياء
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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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