A1 Journal article (refereed)
Non-equilibrium dynamics of a scalar field with quantum backreaction (2021)
Kainulainen, K., & Koskivaara, O. (2021). Non-equilibrium dynamics of a scalar field with quantum backreaction. Journal of High Energy Physics, 2021(12), Article 190. https://doi.org/10.1007/jhep12(2021)190
JYU authors or editors
Publication details
All authors or editors: Kainulainen, Kimmo; Koskivaara, Olli
Journal or series: Journal of High Energy Physics
ISSN: 1126-6708
eISSN: 1029-8479
Publication year: 2021
Volume: 2021
Issue number: 12
Article number: 190
Publisher: Springer
Publication country: Germany
Publication language: English
DOI: https://doi.org/10.1007/jhep12(2021)190
Publication open access: Openly available
Publication channel open access: Open Access channel
Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/79284
Web address of parallel published publication (pre-print): https://arxiv.org/abs/2105.09598
Abstract
We study the dynamical evolution of coupled one- and two-point functions of a scalar field in the 2PI framework at the Hartree approximation, including backreaction from out-of-equilibrium modes. We renormalize the 2PI equations of motion in an on-shell scheme in terms of physical parameters. We present the Hartree-resummed renormalized effective potential at finite temperature and critically discuss the role of the effective potential in a non-equilibrium system. We follow the decay and thermalization of a scalar field from an initial cold state with all energy stored in the potential, into a fully thermalized system with a finite temperature. We identify the non-perturbative processes of parametric resonance and spinodal instability taking place during the reheating stage. In particular we study the unstable modes in the region where the vacuum 1PI effective action becomes complex and show that such spinodal modes can have a dramatic effect on the evolution of the one-point function. Our methods can be easily adapted to simulate reheating at the end of inflation.
Keywords: particle physics; cosmology; quantum field theory
Free keywords: nonperturbative effects; thermal field theory; quantum dissipative systems
Contributing organizations
Related projects
- Dark Universe
- Kainulainen, Kimmo
- Research Council of Finland
Ministry reporting: Yes
Reporting Year: 2021
JUFO rating: 2