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Analytic continuation of thermal N-point functions from imaginary to real energies

R. Baier

A. Niégawa

  • Fakultät für Physik, Universität Bielefeld, 33501 Bielefeld, Germany

  • Department of Physics, Osaka City University, Sumiyoshi-ku, Osaka 558, Japan

Phys. Rev. D 49, 4107 – Published 15 April, 1994

DOI: https://doi.org/10.1103/PhysRevD.49.4107

Abstract

Thermal n-point Green functions in the framework of quantum field theory at finite temperature are considered. We reanalyze how analytic continuations from imaginary to real energies relate these functions originally defined in the imaginary-time formalism to retarded and advanced realtime ones. We described a new and rather simple method which is valid to all orders of perturbation theory and which has the further advantage that it is independent of approximations often applied in actual finite-order calculations.

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