Two projective measurements sequentially performed on a quantum system is studied in the case that the order of the measurements is completely indefinite. The interference of the different orders provides the Kirkwood-Dirac distribution of a quantum system to be measured and thus the weak value of an observable can be obtained without weak measurement. In an interferometric setting, the Kirkwood-Dirac distribution can be constructed from conditional visibility and phase shift.

中文翻译：

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关于因果顺序不确定的顺序测量

在测量顺序完全不确定的情况下，研究了在量子系统上依次执行的两个投影测量。不同阶数的干涉提供了要测量的量子系统的Kirkwood-Dirac分布，因此无需弱测量即可获得可观测值的弱值。在干涉仪设置中，可以根据条件可见性和相移来构造Kirkwood-Dirac分布。