论文标题
多轮过程矩阵
The Multi-round Process Matrix
论文作者
论文摘要
我们开发了过程矩阵（PM）框架的扩展，用于量子操作之间的相关性，而没有因果秩序，该量子允许兼顾各方的多个回合信息交换，并在当地的事件的假设上兼容。我们表征了描述此类相关性的高阶过程，我们将其命名为多轮过程矩阵（MPM），并提出了因果关系不可分割性的概念，该概念扩展了标准PMS的因果关系。我们表明，在多轮案例中，有因果不可分割性的新颖表现并非被标准PM形式主义的幼稚应用所捕获：我们展示了操作员的实例，该实例既是有效的PM，又是有效的MPM，但在第一种情况下是可分离的，并且由于使用侧频道而在第二种情况下可以违反第二种情况。
We develop an extension of the process matrix (PM) framework for correlations between quantum operations with no causal order that allows multiple rounds of information exchange for each party compatibly with the assumption of well-defined causal order of events locally. We characterise the higher-order process describing such correlations, which we name the multi-round process matrix (MPM), and formulate a notion of causal nonseparability for it that extends the one for standard PMs. We show that in the multi-round case there are novel manifestations of causal nonseparability that are not captured by a naive application of the standard PM formalism: we exhibit an instance of an operator that is both a valid PM and a valid MPM, but is causally separable in the first case and can violate causal inequalities in the second case due to the possibility of using a side channel.
