The Finite-Temperature Feynman Propagator in Operator Form

Abstract

In momentum space the Feynman propagator $D_F(k)$ at non-zero temperature is defined by a simple dispersion relation with the familiar property of being an even function of $k^0$ and analytic for Re$(k^0{)}^2>0$. The coordinate space form of the propagator $D_F(x)$ is expressed directly in terms of matrix elements of the field operator and requires a new type of operator ordering.

Comments: 9 pages plain TeX