THE FEYNMAN DIAGRAMMATIC TECHNIQUE FOR THE DOUBLE TIME DEPENDENT CAUSAL GREEN''S FUNCTION
双时因果格林函数的费曼图解法

Starting from the discussion of analytic properties and using the Landau relation to improve the diagrammatic technique of Dzyaloshinskii, the Feynman diagrammatic technique for double time dependent causal Green's function is established. There is a correct limit of zero temperature and may be used to calculate the various dynamical properties of nonequlibrium processes.