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A measurable entanglement criterion for two qubits

Hoshang Heydari·Gunnar Björk·Luis Sánchez-Soto
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Abstract

We propose a directly measurable criterion for the entanglement of two qubits. We compare the criterion with other criteria, and we find that for pure states, and some mixed states, it coincides with the state's concurrency. The measure can be obtained with a Bell state analyser and the ability to make general local unitary transformations. However, the procedure fails to measure the entanglement of a general mixed two-qubit state.

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Hoshang Heydari, Gunnar Björk, Luis Sánchez-Soto. 2003-10-06. A measurable entanglement criterion for two qubits. https://doi.org/10.1103/physreva.68.062314

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