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Optimal estimation of two-qubit pure-state entanglement

A. Acin·R. Tarrach·G. Vidal
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Abstract

We present optimal measuring strategies for the estimation of the entanglement of unknown two-qubit pure states and of the degree of mixing of unknown single-qubit mixed states, of which N identical copies are available. The most general measuring strategies are considered in both situations, to conclude in the first case that a local, although collective, measurement suffices to estimate entanglement, a non-local property, optimally.

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A. Acin, R. Tarrach, G. Vidal. 1999-11-03. Optimal estimation of two-qubit pure-state entanglement. https://doi.org/10.1103/physreva.61.062307

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