Gühne O, Reimpell M, Werner R F
Institut für Quantenoptik und Quanteninformation, Osterreichische Akademie der Wissenschaften, A-6020 Innsbruck, Austria.
Phys Rev Lett. 2007 Mar 16;98(11):110502. doi: 10.1103/PhysRevLett.98.110502.
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.
我们提出了一种在实验中估计纠缠度量的方法。我们展示了如何从任何有限纠缠见证者集合的测量期望值中推导出一般纠缠度量的下限。因此，无需进一步的实验数据，见证者测量就具有了定量意义。我们将我们的结果应用于最近的一个多光子实验[M. 布伦南，《物理评论快报》92, 087902 (2004)]，给出了该实验中形成纠缠和几何纠缠度量的界限。
