Fig. 8
From: Path Integral Methods for Stochastic Differential Equations
(a)Â Diagrammatic expansion for the two-point correlation \(\langle v(t) v(t') \rangle\), showing the tree level and an example one-loop graph. Diagrams for (b)Â \(\langle w(t) w(t') \rangle\) and (c)Â \(\langle v(t) w(t') \rangle\) are topologically identical with the replacement of the appropriate external lines by the \(G^{v}_{\omega}(t,t')\) propagator