Measuring quantum entanglement without prior state reconstruction

Pawel Horodecki

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Measuring quantum entanglement without prior state reconstruction

Pawel Horodecki

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Abstract

It is shown that, despite strong nonlinearity, entanglement of formation of two-qubit state can be measured without prior state reconstruction. Collective measurements on small number of copies are provided that allow to determine quantum concurrence {\it via} estimation of only {\it four} parameters. It is also pointed out that another entanglement measure based on so called negativity can also be measured in similar way. The result is related to general problem: what kind of information can be extracted efficiently from unknown quantum state ?

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Pawel Horodecki. 2002-12-05. Measuring quantum entanglement without prior state reconstruction. https://arxiv.org/abs/quant-ph/0111082

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