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Another convex combination of product states for the separable Werner state

Hiroo Azuma·Masashi Ban
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Abstract

In this paper, we write down the separable Werner state in a two-qubit system explicitly as a convex combination of product states, which is different from the convex combination obtained by Wootters' method. The Werner state in a two-qubit system has a single real parameter and varies from inseparable state to separable state according to the value of its parameter. We derive a hidden variable model that is induced by our decomposed form for the separable Werner state. From our explicit form of the convex combination of product states, we understand the following: The critical point of the parameter for separability of the Werner state comes from positivity of local density operators of the qubits.

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Hiroo Azuma, Masashi Ban. 2006-02-09. Another convex combination of product states for the separable Werner state. https://doi.org/10.1103/physreva.73.032315

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