Here we introduce the concept of classical input – quantum output (C-Q) non-signalling boxes, a generalisation of the classical input – classical output (C-C) non-signalling boxes. We argue that studying such objects leads to a better understanding of the relation between quantum nonlocality and non-locality beyond quantum mechanics. The main issue discussed in the paper is whether there exist 'genuine' C-Q boxes or all C-Q boxes can be built from objects already known, namely C-C boxes acting on pre-shared entangled quantum particles. We show that large classes of C-Q boxes are non-genuine. In particular, we show that all bi-partite C-Q boxes with outputs that are pure states are non-genuine. We also present various strategies for addressing the general problem, i.e. for multi-partite C-Q boxes which output mixed states, whose answer is still open. Finally, we show that even some very simple non-genuine C-Q boxes require large amounts of C-C nonlocal correlations in order to simulate them.

中文翻译：

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经典到量子非信号盒


这里我们引入经典输入-量子输出（CQ）非信令盒的概念，是经典输入-经典输出（CC）非信令盒的推广。我们认为，研究这些物体可以更好地理解量子非定域性和量子力学之外的非定域性之间的关系。论文讨论的主要问题是是否存在“真正的”CQ 盒，或者所有 CQ 盒都可以从已知的对象构建，即作用于预先共享的纠缠量子粒子的 CC 盒。我们证明大部分 CQ 盒子都是假的。特别是，我们证明所有输出为纯状态的二分 CQ 盒都是非真实的。我们还提出了解决一般问题的各种策略，即输出混合状态的多方 CQ 盒，其答案仍然是开放的。最后，我们表明，即使是一些非常简单的非真实 CQ 框也需要大量的 CC 非局部相关性才能对其进行模拟。