Salavrakos Alexia, Augusiak Remigiusz, Tura Jordi, Wittek Peter, Acín Antonio, Pironio Stefano
ICFO-Institut de Ciencies Fotoniques, Barcelona Institute of Science and Technology, 08860 Castelldefels, Barcelona, Spain.
Center for Theoretical Physics, Polish Academy of Sciences, Aleja Lotników 32/46, 02-668 Warsaw, Poland.
Phys Rev Lett. 2017 Jul 28;119(4):040402. doi: 10.1103/PhysRevLett.119.040402. Epub 2017 Jul 26.
Bell inequalities have traditionally been used to demonstrate that quantum theory is nonlocal, in the sense that there exist correlations generated from composite quantum states that cannot be explained by means of local hidden variables. With the advent of device-independent quantum information protocols, Bell inequalities have gained an additional role as certificates of relevant quantum properties. In this work, we consider the problem of designing Bell inequalities that are tailored to detect maximally entangled states. We introduce a class of Bell inequalities valid for an arbitrary number of measurements and results, derive analytically their tight classical, nonsignaling, and quantum bounds and prove that the latter is attained by maximally entangled states. Our inequalities can therefore find an application in device-independent protocols requiring maximally entangled states.
传统上，贝尔不等式被用于证明量子理论是非定域的，即存在由复合量子态产生的关联，这些关联无法用局域隐变量来解释。随着与设备无关的量子信息协议的出现，贝尔不等式获得了作为相关量子特性证明的额外作用。在这项工作中，我们考虑设计专门用于检测最大纠缠态的贝尔不等式的问题。我们引入了一类对任意数量的测量和结果都有效的贝尔不等式，通过分析得出它们严格的经典、无信号和量子界限，并证明最大纠缠态能达到后者。因此，我们的不等式可应用于需要最大纠缠态的与设备无关的协议中。
