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arXiv · 1912.07565

Spectral, statistical and vertex functions in scalar quantum field theory far from equilibrium

Linda Shen·Jürgen Berges
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Abstract

We compute the far-from-equilibrium dynamics of relativistic scalar quantum fields in 3+1 space-time dimensions starting from over-occupied initial conditions. We determine universal scaling exponents and functions for two-point correlators and the four-vertex in a self-similar regime in time and space or momenta. The scaling form of the momentum-dependent four-vertex exhibits a dramatic fall-off towards low momenta. Comparing spectral functions (commutators) and statistical correlations (anti-commutators) of field operators allows us to detect strong violations of the fluctuation-dissipation relation in this non-perturbative infrared regime. Based on a self-consistent expansion in the number of field components to next-to-leading order, a wide range of interaction strengths is analyzed and compared to weak-coupling estimates in effective kinetic theory and classical-statistical field theory.

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Linda Shen, Jürgen Berges. 2019-12-16. Spectral, statistical and vertex functions in scalar quantum field theory far from equilibrium. https://doi.org/10.1103/physrevd.101.056009

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