标题： 离散时间量子行走：连续极限和对称性 显示英文标题

标题： Discrete-time quantum walks: continuous limit and symmetries

摘要： 一维离散时间量子行走的连续极限随着时间和空间相关系数的变化而被研究。 给定的量子行走通常不承认连续极限，但某些族（1-喷束）确实可以。 所有承认连续极限的族（1-喷束）都被识别出来。 连续极限由狄拉克型方程描述，或者交替地由一对克莱因-戈登方程描述。 这些方程所引导的变分原理以及局部不变性性质也被讨论。 显示英文摘要

摘要： The continuous limit of one dimensional discrete-time quantum walks with time- and space-dependent coefficients is investigated. A given quantum walk does not generally admit a continuous limit but some families (1-jets) of quantum walks do. All families (1-jets) admitting a continuous limit are identified. The continuous limit is described by a Dirac-like equation or, alternately, a couple of Klein-Gordon equations. Variational principles leading to these equations are also discussed, together with local invariance properties.