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Transformations of real-time finite-temperature Feynman rules

M. A. van Eijck·R. Kobes·Ch. G. van Weert
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Abstract

We consider transformations of the $2\times2$ propagator matrix in real-time finite-temperature field theory, resulting in transformed $n$--point functions. As special cases of such a transformation we examine the Keldysh basis, the retarded/advanced $RA$ basis, and a Feynman-like $F\bar F$ basis, which differ in this context as to how ``economically'' certain constraints on the original propagator matrix elements are implemented. We also obtain the relation between some of these real-time functions and certain analytic continuations of the imaginary-time functions. Finally, we compare some aspects of these bases which arise in practical calculations.

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M. A. van Eijck, R. Kobes, Ch. G. van Weert. 1994-06-02. Transformations of real-time finite-temperature Feynman rules. https://doi.org/10.1103/physrevd.50.4097

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