Effective convergence of the 2PI-1/N expansion for nonequilibrium quantum fields

Abstract

The 1/N expansion of the two-particle irreducible effective action offers a powerful approach to study quantum field dynamics far from equilibrium. We investigate the effective convergence of the 1/N expansion in the O(N) model by comparing results obtained numerically in 1+1 dimensions at leading, next-to-leading and next-to-next-to-leading order in 1/N as well as in the weak coupling limit. A comparison in classical statistical field theory, where exact numerical results are available, is made as well. We focus on early-time dynamics and quasi-particle properties far from equilibrium and observe rapid effective convergence already for moderate values of 1/N or the coupling.

4 pages, 4 eps figures

References in corpus (6)

• Non-thermal fixed points: effective weak-coupling for strongly correlated systems far from equilibrium
• Quantum field thermalization in expanding backgrounds
• The pressure of QED from the two-loop 2PI effective action
• Ward Identities for the 2PI effective action in QED
• Thermal effects on slow-roll dynamics
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Cited by in corpus (1)

• Nonthermal fixed points and the functional renormalization group