Naturwissenschaftlich-Technische Fakultät, Universität Siegen, Walter-Flex-Strasse 3, D-57068 Siegen, Germany.
Phys Rev Lett. 2013 Jul 19;111(3):030501. doi: 10.1103/PhysRevLett.111.030501. Epub 2013 Jul 15.
We present a general method to quantify both bipartite and multipartite entanglement in a device-independent manner, meaning that we put a lower bound on the amount of entanglement present in a system based on the observed data only but independent of any quantum description of the employed devices. Some of the bounds we obtain, such as for the Clauser-Horne-Shimony-Holt Bell inequality or the Svetlichny inequality, are shown to be tight. Besides, device-independent entanglement quantification can serve as a basis for numerous tasks. We show in particular that our method provides a rigorous way to construct dimension witnesses, gives new insights into the question whether bound entangled states can violate a Bell inequality, and can be used to construct device-independent entanglement witnesses involving an arbitrary number of parties.
我们提出了一种通用的方法，可以以设备独立的方式对双量子位和多量子位纠缠进行定量，这意味着我们仅基于观察到的数据对系统中存在的纠缠量进行下界估计，而与所使用设备的任何量子描述无关。我们得到的一些界限，例如克劳瑟-霍恩-斯希莫尼-霍尔特贝尔不等式或斯维特利希尼不等式，被证明是紧密的。此外，设备独立的纠缠量化可以作为许多任务的基础。我们特别表明，我们的方法为构造维数见证者提供了一种严格的方法，为绑定纠缠态是否可以违反贝尔不等式的问题提供了新的见解，并可用于构造涉及任意数量的当事方的设备独立的纠缠见证者。
