Optimum Filtering Taking Quantum Effects into Account

The quantum problems of the detection of electromagnetic signals on a background of noise when the receiver measures the intensity of the radiation field or its square are considered. Using the maximum disinformation principle, the matrices of the density of states of the radiation with known spectral components of the signal and noise and given form of the total output signal are obtained. Calculation of the parameters of the useful signal using these matrices leads to a quantum formula of optimum filtering, which reduces to the classical formula at low frequencies.