论文标题
评论“重新访问量子因果结构的动态 - 因果秩序如何发展？''
Comment on "Revisiting dynamics of quantum causal structures --when can causal order evolve?''
论文作者
论文摘要
在过去的几年中，对无限因子秩序的量子过程一直在增加兴趣。过程矩阵是研究此类过程的方便框架。参考。 [1]定义了从过程矩阵到过程矩阵的高阶转换，并表明没有连续和可逆的转换可以改变过程矩阵的因果阶。参考。 [2]基于一组示例，在某些情况下，过程可以随着时间的流逝而改变其因果秩序。参考。 [2]声称，高阶转换的形式主义不足以捕获其例子。在这里，我们表明这种说法是不正确的。此外，参考文献的关键例子。 [2]在参考文献中已经明确考虑了。 [1]并显示与其结果兼容。
In the last few years, there has been increasing interest in quantum processes with indefinite causal order. Process matrices are a convenient framework to study such processes. Ref. [1] defines higher order transformations from process matrices to process matrices and shows that no continuous and reversible transformation can change the causal order of a process matrix. Ref. [2] argues, based on a set of examples, that there are situations where a process can change its causal order over time. Ref. [2] claims that the formalism of higher order transformations is not general enough to capture its examples. Here we show that this claim is incorrect. Moreover, a crucial example of Ref. [2] has already been explicitly considered in Ref. [1] and shown to be compatible with its results.
