Institut de Ciencies Fotoniques, Barcelona, Spain.
Phys Rev Lett. 2012 Aug 17;109(7):070401. doi: 10.1103/PhysRevLett.109.070401.
Because of the importance of entanglement for quantum information purposes, a framework has been developed for its characterization and quantification as a resource based on the following operational principle: entanglement among N parties cannot be created by local operations and classical communication, even when N-1 parties collaborate. More recently, nonlocality has been identified as another resource, alternative to entanglement and necessary for device-independent quantum information protocols. We introduce an operational framework for nonlocality based on a similar principle: nonlocality among N parties cannot be created by local operations and allowed classical communication even when N-1 parties collaborate. We then show that the standard definition of multipartite nonlocality, due to Svetlichny, is inconsistent with this operational approach: according to it, genuine tripartite nonlocality could be created by two collaborating parties. We finally discuss alternative definitions for which consistency is recovered.
由于纠缠对于量子信息目的非常重要，因此已经开发了一种基于以下操作原理的纠缠特性描述和量化框架：即使 N-1 方合作，N 方之间的纠缠也不能通过本地操作和经典通信来创建。最近，非局域性已被确定为另一种资源，它与纠缠不同，对于设备无关的量子信息协议是必要的。我们基于类似的原理引入了一种用于非局域性的操作框架：即使 N-1 方合作，N 方之间的非局域性也不能通过本地操作和允许的经典通信来创建。然后，我们表明，由于 Svetlichny 提出的多体非局域性的标准定义与这种操作方法不一致：根据该定义，两个合作方可以创建真正的三方非局域性。最后，我们讨论了恢复一致性的替代定义。
