论文标题
一般多部分状态和渠道的新兴经典性
Emergent classicality in general multipartite states and channels
论文作者
论文摘要
在量子测量过程中，有关测量系统的经典信息在整个环境中扩散。同时，对于本地观察者，有关系统的量子信息变得无法访问。在这里，我们证明了量子通道的结果，表明该现象的一个方面是完全一般的。我们表明，对于系统和环境的任何演变，对于我们称为“量子马尔可夫毛毯”的$ O（1）$大小的区域的任何地方，有关系统的任何本地访问的信息都必须大致是经典的，即可以从一些固定的测量中获得。结果增强了ARXIV：1310.8640的较早结果，其中被排除的区域被允许随环境规模增长。它也可以看作是无裁决或一夫一妻制的原则的新结果。我们的证明提供了一个建设性的优化程序，用于确定“量子马尔可夫毯”区域以及进化引起的有效测量。另外，在通道状态二元性下，我们的结果表征了多方状态的边际。
In a quantum measurement process, classical information about the measured system spreads throughout the environment. Meanwhile, quantum information about the system becomes inaccessible to local observers. Here we prove a result about quantum channels indicating that an aspect of this phenomenon is completely general. We show that for any evolution of the system and environment, for everywhere in the environment excluding an $O(1)$-sized region we call the "quantum Markov blanket," any locally accessible information about the system must be approximately classical, i.e. obtainable from some fixed measurement. The result strengthens the earlier result of arXiv:1310.8640 in which the excluded region was allowed to grow with total environment size. It may also be seen as a new consequence of the principles of no-cloning or monogamy of entanglement. Our proof offers a constructive optimization procedure for determining the "quantum Markov blanket" region, as well as the effective measurement induced by the evolution. Alternatively, under channel-state duality, our result characterizes the marginals of multipartite states.
