Measurements of negative joint probabilities in optical quantum system
Measurements of negative joint probabilities in optical quantum system
复制标题
光量子系统负联合概率的测量
DOI：
10.1007/978-4-431-55429-5_4
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
H.F.Hofmann
中科院分区：
文献类型：
--
作者：
M.Iinuma;Y.Suzuki;H.F.Hofmann
量子信息科学是以量子态的叠加原理和非局域量子关联为基础的。这些非经典性质仍然是神秘的，作为物理现象没有得到充分的理解。无法解决这类问题的最大原因是我们不能直接得到量子态的全部裸信息，因为任何测量的作用都绝对改变了量子态。最近，我们实现了光子偏振的可变强度测量，它能够控制测量强度从零（无测量）到完全投影（完全破坏性测量）。该装置使得有可能执行两个非交换可观测量的误差和测量产生的反作用效应，这永远不会同时给出准确的值的顺序测量。我们调查的第一个变量强度测量的测量不确定度的作用。实验获得的联合概率可以被认为是由随机极化翻转所获得的统计混合，该随机极化翻转引起的测量不确定性来自内在的联合概率分布。这个自然的假设提供了从实验概率中去除反作用效应，并且所获得的固有概率导致负值。该分析还显示了如何通过分辨率和反作用不确定性的可变组合将负概率转换为可观察的正统计。
Quantum information science is based on the superposition principle and the non-local quantum correlation of quantum states. These non-classical properties are still mysterious and inadequately understood as physical phenomena. The biggest reason to un-resolving such problems is that we can directly not get all bare information of the quantum states since an action by any measurement absolutely changes the quantum states. Recently, we realized a variable strength measurement of photon polarization, which is capable of controlling the measurement strength from zero (no measurement) to fully projection (completely destructive measurement). This apparatus makes it possible to perform a sequential measurement of two non-commuting observables with an error and the back-action effects produced by the measurement, which never gives exact values simultaneously. We investigated the role of measurement uncertainties of the first variable strength measurement. The experimentally-obtained joint probabilities can be recognized as statistical mixture obtained by random polarization flips arising the measurement uncertainties from an intrinsic joint probability distribution. This natural assumption provided a removal of the back-action effect from the experimental probabilities and the obtained intrinsic probabilities resulted in negative. This analysis also shows how the negative probabilities are converted to observable positive statistics by variable combinations of resolution and back-action uncertainties.