Masanes Lluís
School of Mathematics, University of Bristol, Bristol BS8 1TW, United Kingdom.
Phys Rev Lett. 2006 Aug 4;97(5):050503. doi: 10.1103/PhysRevLett.97.050503. Epub 2006 Aug 3.
A multipartite quantum state violates a Bell inequality asymptotically if, after jointly processing by general local operations an arbitrarily large number of copies of it, the result violates the inequality. In the bipartite case we show that asymptotic violation of the Clauser-Horne-Shimony-Holt inequality is equivalent to distillability. Hence, bound entangled states do not violate it. In the multipartite case we consider the complete set of full-correlation Bell inequalities with two dichotomic observables per site. We show that asymptotic violation of any of these inequalities by a multipartite state implies that pure-state entanglement can be distilled from it, although the corresponding distillation protocol may require that some of the parties join into several groups. We also obtain the extreme points of the set of distributions generated by measuring N quantum systems with two dichotomic observables per site.
如果一个多方量子态在通过一般局部操作联合处理任意大量的该态副本后，结果违反了某个贝尔不等式，那么该多方量子态就渐近地违反了这个贝尔不等式。在两方情形下，我们证明了渐近违反克劳泽 - 霍恩 - 希莫尼 - 霍尔特不等式等同于可提纯性。因此，束缚纠缠态并不违反它。在多方情形下，我们考虑每个位点有两个二分可观测量的完全关联贝尔不等式的完备集。我们证明，一个多方态渐近违反这些不等式中的任何一个意味着可以从该态中提纯出纯态纠缠，尽管相应的提纯协议可能要求一些参与方联合成几个组。我们还得到了通过对每个位点有两个二分可观测量的(N)个量子系统进行测量所生成的分布集的极点。
