Correlation theory of quantized electromagnetic field II

Some general properties of a correlation matrix which has been defined in recent paper are investigated. The cross-symmetry condition and the non-negative-definiteness condition for the arbitrary order correlation matrix of an electromagnetic field are derived. Further, the stationarity condition in terms of time derivatives of the correlation matrix as well as a necessary condition of the stationarity of the electromagnetic field by means of the generalized Wiener-Khinchin theorem are obtained. With the help of the new form of the stationarity condition a connection between this condition and monochromacity of a coherent field is shown.The author wishes to thank Dr. J. Peina for discussions.