Quantification of Concurrence via Weak Measurement
arXiv:1611.00149 · doi:10.1103/PhysRevA.95.052301
Abstract
Since entanglement is not an observable per se, measuring its value in practice is a difficult task. Here we propose a protocol for quantifying a particular entanglement measure, namely concurrence, of an arbitrary two-qubit pure state via a single fixed measurement set-up by exploiting so-called weak measurements and the associated weak values together with the properties of the Laguerre-Gaussian modes. The virtue of our technique is that it is generally applicable for all two-qubit systems and does not involve simultaneous copies of the entangled state. We also propose an explicit optical implementation of the protocol.
7 pages, 2 figures. Final ver 3: An appendix explaining the robustness of our method was addded
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