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Remarks on 2-q-bit states

Berthold-Georg Englert·Nasser Metwally
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Abstract

We distinguish six classes of families of locally equivalent states in a straightforward scheme for classifying all 2-q-bit states; four of the classes consist of two subclasses each. The simple criteria that we stated recently for checking a given state's positivity and separability are justified, and we discuss some important properties of Lewenstein-Sanpera decompositions. An upper bound is conjectured for the sum of the degree of separability of a 2-q-bit state and its concurrence.

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Berthold-Georg Englert, Nasser Metwally. 2000-07-17. Remarks on 2-q-bit states. https://doi.org/10.1007/s003400000502

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