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

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.

15 pages, 12 figures

References in corpus (3)

• Non-thermal fixed points: effective weak-coupling for strongly correlated systems far from equilibrium
• Nonthermal fixed points and the functional renormalization group
• Strong versus weak wave-turbulence in relativistic field theory

Cited by in corpus (10)

• QCD thermalization: Ab initio approaches and interdisciplinary connections
• Spectral functions in the ${\varphi }^4$-theory from the spectral DSE
• Spectral functions from the real-time functional renormalization group
• Flowing with the Temporal Renormalisation Group
• Universal dynamics and non-thermal fixed points in quantum fluids far from equilibrium
• Broad excitations in a 2+1D overoccupied gluon plasma
• Stability analysis of non-thermal fixed points in longitudinally expanding kinetic theory
• Thermalization and dynamical spectral properties in the quark-meson model
• Detecting defect dynamics in relativistic field theories far from equilibrium using topological data analysis
• Kelvin waves in nonequilibrium universal dynamics of relativistic scalar field theories