标题： 存在非正交的量子测量是完全可重复的 显示英文标题

标题： There exist non orthogonal quantum measurements that are perfectly repeatable

摘要： 我们证明，与普遍信念相反，在量子力学中可重复的测量不一定由正交投影算子描述——这是“可观测量”的传统范式。然而，非正交可重复性仅在无限维情况下出现。我们还证明，当进行非正交可重复测量时，被测量的系统会保留一些“记忆”，即测量次数的信息。 显示英文摘要

摘要： We show that, contrarily to the widespread belief, in quantum mechanics repeatable measurements are not necessarily described by orthogonal projectors--the customary paradigm of "observable". Nonorthogonal repeatability, however, occurs only for infinite dimensions. We also show that when a non orthogonal repeatable measurement is performed, the measured system retains some "memory" of the number of times that the measurement has been performed.