We employ the functional renormalization group approach formulated on the Schwinger-Keldysh contour to calculate real-time correlation functions in scalar field theories. We provide a detailed description of the formalism, discuss suitable truncation schemes for real-time calculations as well as the numerical procedure to self-consistently solve the flow equations for the spectral function. Subsequently, we discuss the relations to other perturbative and non-perturbative approaches to calculate spectral functions, and present a detailed comparison and benchmark in d=0+1 dimensions.
@article{arxiv.2009.04194,
title = {Spectral functions from the real-time functional renormalization group},
author = {Sven Huelsmann and Soeren Schlichting and Philipp Scior},
journal= {arXiv preprint arXiv:2009.04194},
year = {2020}
}