TRANSFORMATIONS OF REAL-TIME FINITE-TEMPERATURE FEYNMAN-RULES

We consider transformations of the 2 x 2 propagator matrix in real-tim e finite-temperature field theory, resulting in transformed n-point fu nctions. As special cases of such a transformation we examine the Keld ysh basis, the retarded/advanced RA basis, and a Feynman-like <F(F)ove r bar> basis, which differ in this context as to how ''economically'' certain constraints on the original propagator matrix elements are imp lemented. We also obtain the relation between some of these real-time functions and certain analytic continuations of the imaginary-time fun ctions. Finally, we compare some aspects of these bases which arise in practical calculations.