Nonthermal fixed points and the functional renormalization group

TL;DR

This paper explores nonthermal fixed points in quantum field theories using the functional renormalization group, revealing a hierarchy of solutions from equilibrium to nonequilibrium states.

Contribution

It introduces a unified framework based on the functional renormalization group on a real-time path to analyze nonthermal fixed points in quantum field theories.

Findings

Identifies a hierarchy of fixed point solutions

Demonstrates the framework's applicability to O(N) scalar theories

Shows increasing complexity from equilibrium to nonequilibrium fixed points

Abstract

Nonthermal fixed points represent basic properties of quantum field theories, in addition to vacuum or thermal equilibrium fixed points. The functional renormalization group on a closed real-time path provides a common framework for their description. For the example of an O(N) symmetric scalar theory it reveals a hierarchy of fixed point solutions, with increasing complexity from vacuum and thermal equilibrium to nonequilibrium.