Coiteux-Roy Xavier, Makuta Owidiusz, Curran Fionnuala, Augusiak Remigiusz, Renou Marc-Olivier
Department of Computer Science, University of Calgary, Calgary, Canada.
Department of Physics and Astronomy, University of Calgary, Calgary, Canada.
npj Quantum Inf. 2025;11(1):90. doi: 10.1038/s41534-025-01024-x. Epub 2025 Jun 2.
The notion of genuinely multipartite nonlocality (GMNL) was introduced to conceptualize the fact that nonclassical resources involving more than two parties in a nontrivial way may be needed to account for some quantum correlations. In this letter, we first recall the contradictions inherent to the historical definition of GMNL. Second, we turn to one of its redefinitions, called Local-Operations-and-Shared-Randomness GMNL (LOSR-GMNL), proving that all caterpillar graph states (including linear cluster states) have this second property. Finally, we conceptualize a third, alternative definition, which we call Local-Operations-and-Neighbour-Communication GMNL (LONC-GMNL), that is adapted to situations in which short-range communication between some parties might occur. We show that linear cluster states do not have this third property, while GHZ states do. Beyond its technical content, our letter illustrates that rigorous conceptual work is needed before applying the concepts of multipartite nonlocality or entanglement to benchmark the nonclassicality of some experimentally-produced quantum systems.
真正的多方非定域性(GMNL)概念的引入是为了概念化这样一个事实:可能需要以一种非平凡的方式涉及多于两方的非经典资源来解释某些量子关联。在这封信中,我们首先回顾GMNL历史定义中固有的矛盾。其次,我们转向其重新定义之一,称为局部操作与共享随机性GMNL(LOSR - GMNL),证明所有毛毛虫图态(包括线性簇态)都具有这第二种性质。最后,我们概念化了第三种替代定义,我们称之为局部操作与邻域通信GMNL(LONC - GMNL),它适用于某些方之间可能发生短程通信的情况。我们表明线性簇态不具有这第三种性质,而GHZ态具有。除了其技术内容外,我们的信还表明,在应用多方非定域性或纠缠概念来衡量某些实验产生的量子系统的非经典性之前,需要进行严格的概念性工作。