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Optimal Entanglement Enhancement for Mixed States

Adrian Kent·Noah Linden·Serge Massar
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Abstract

We consider the actions of protocols involving local quantum operations and classical communication (LQCC) on a single system consisting of two separated qubits. We give a complete description of the orbits of the space of states under LQCC and characterise the representatives with maximal entanglement of formation. We thus obtain a LQCC entanglement concentration protocol for a single given state (pure or mixed) of two qubits which is optimal in the sense that the protocol produces, with non-zero probability, a state of maximal possible entanglement of formation. This defines a new entanglement measure, the maximum extractable entanglement.

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Adrian Kent, Noah Linden, Serge Massar. 1999-09-04. Optimal Entanglement Enhancement for Mixed States. https://doi.org/10.1103/physrevlett.83.2656

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