AI 中文总结
该研究在历史理论框架下，揭示过程矩阵不定因果序是动力学叠加的操作受限实现，明确事件序与干预序的区别，阐明不定因果序、量子动力学与时空结构的关联。
AI 中文摘要
过程矩阵形式主义描述不假设固定全局因果序的量子过程，但不定因果序的物理意义仍未明确。我们在历史理论中研究该问题，其中时间序和动力学演化是不同结构。我们证明退相干泛函允许动力学的相干叠加；在测量场景中，满足合适的分解条件时，这些叠加会生成过程矩阵。因此，我们将过程矩阵不定因果序确定为更普遍的动力学叠加现象在操作层面受限的实现。历史理论还包含一种独特的不定序运动学概念，其中物理事件的序本身是历史可观测量。事件序与干预序的这一区别，阐明了不定因果序、量子动力学与时空结构之间的关系。
英文摘要
The process-matrix formalism describes quantum processes without assuming a fixed global causal order, but the physical meaning of indefinite causal order remains open. We address this question within histories theory, where temporal ordering and dynamical evolution are distinct structures. We show that the decoherence functional admits coherent superpositions of dynamics. In measurement settings, under suitable factorization conditions, these generate process matrices. Thus, we identify process-matrix indefinite causal order as an operationally restricted realization of the more general phenomenon of superposition of dynamics. Histories theory also admits a distinct kinematical notion of indefinite order, in which the ordering of physical events is itself a history observable. The resulting distinction between event order and intervention order clarifies the relation between indefinite causal order, quantum dynamics, and spacetime structure.
Comments24 pages, 1 figure
