Estimating entanglement measures in experiments.
We present a method to estimate entanglement measures in experiments. We show how a lower bound on a generic entanglement measure can be derived from the measured expectation values of any finite collection of entanglement witnesses. Hence witness measurements are given a quantitative meaning without the need of further experimental data. We apply our results to a recent multiphoton experiment [M. Bourennane, Phys. Rev. Lett. 92, 087902 (2004)], giving bounds on the entanglement of formation and the geometric measure of entanglement in this experiment.
Gühne
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Institut für Quantenoptik und Quanteninformation, Osterreichische Akademie der Wissenschaften, A-6020 Innsbruck, Austria.
Reimpell
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M
Werner
R F
RF