Quantum theory of successive projective measurements
Quantum theory of successive projective measurements
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DOI：
10.1103/physreva.76.012119
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发表时间：
2007-07-01
影响因子：
2.9
通讯作者：
Johansen, Lars M.
中科院分区：
文献类型：
--
作者：
Johansen, Lars M.
我们证明了一个量子态可以表示为一个联合概率和一个复量子修正项的和。在连续射影测量中可以观察到联合概率和修正项。复修正项是测量扰动的一种度量。需要选择相位旋转来获得虚部。这导致了一个复杂的准概率：柯克伍德分布。我们证明了如果两个观测值是极大和互补的，那么柯克伍德分布包含了关于状态的全部信息。柯克伍德分布给出了国家减少的另一幅图景。在非选择性测量中，修正项消失。选择性测量导致量子态为非负条件概率。我们论证了施温格基的特殊意义。
We show that a quantum state may be represented as the sum of a joint probability and a complex quantum modification term. The joint probability and the modification term can both be observed in successive projective measurements. The complex modification term is a measure of measurement disturbance. A selective phase rotation is needed to obtain the imaginary part. This leads to a complex quasiprobability: The Kirkwood distribution. We show that the Kirkwood distribution contains full information about the state if the two observables are maximal and complementary. The Kirkwood distribution gives another picture of state reduction. In a nonselective measurement, the modification term vanishes. A selective measurement leads to a quantum state as a non-negative conditional probability. We demonstrate the special significance of the Schwinger basis.