We review the method of quantizers and dequantizers to construct an invertible map of the density operators onto functions including probability distributions and discuss in detail examples of qubit and qutrit states. The biphoton states existing in the process of parametric down-conversion are studied in the probability representation of quantum mechanics.

中文翻译：

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Qudit状态和参数下变频的量化器和均衡器运算符的属性

我们回顾了量化器和反量化器的方法，以将密度算符构造为包含概率分布的函数的可逆映射，并详细讨论了量子位和量子态的示例。在量子力学的概率表示中研究了参数下转换过程中存在的双光子态。