Using Gardiner and Collet’s input-output model and the concept of cascade system, we determine the filtering equation for a quantum system driven by light in some specific nonclassical states. The quantum system and electromagnetic field are described by making use of quantum stochastic unitary evolution. We consider two examples of the nonclassical states of field: a combination of vacuum and single photon states and a mixture of two coherent states. The stochastic evolution conditioned on the results of the photon counting and quadrature measurements is described.

中文翻译：

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非经典场驱动系统的量子滤波方程

利用 Gardiner 和 Collet 的输入输出模型和级联系统的概念，我们确定了在某些特定非经典状态下由光驱动的量子系统的滤波方程。利用量子随机酉演化来描述量子系统和电磁场。我们考虑非经典场态的两个例子：真空和单光子态的组合以及两种相干态的混合。描述了以光子计数和正交测量结果为条件的随机演化。