Authors: Mathias Garny, Markus Michael Mueller
The dynamics of quantum fields far from equilibrium can be described by Kadanoff-Baym equations derived from the 2PI effective action. When solving Kadanoff-Baym equations numerically, so far, one usually renormalizes the mass at one-loop level of standard perturbation theory, while keeping the coupling constant unchanged. Recently, however, a completely nonperturbative renormalization procedure for the 2PI effective action has been formulated. We study the impact a nonperturbative renormalization procedure can have on the results given by Kadanoff-Baym equations. We find a significant stabilization of the computational algorithm and substantial quantitative differences, such as an increase of the thermalization times.
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