Oscillating scalar dissipating in a medium
arXiv:2108.00254 · doi:10.1007/JHEP11(2021)160
Abstract
We study how oscillations of a scalar field condensate are damped due to dissipative effects in a thermal medium. Our starting point is a non-linear and non-local condensate equation of motion descending from a 2PI-resummed effective action derived in the Schwinger-Keldysh formalism appropriate for non-equilibrium quantum field theory. We solve this non-local equation by means of multiple-scale perturbation theory appropriate for time-dependent systems, obtaining approximate analytic solutions valid for very long times. The non-linear effects lead to power-law damping of oscillations, that at late times transition to exponentially damped ones characteristic for linear systems. These solutions describe the evolution very well, as we demonstrate numerically in a number of examples. We then approximate the non-local equation of motion by a Markovianised one, resolving the ambiguities appearing in the process, and solve it utilizing the same methods to find the very same leading approximate solution. This comparison justifies the use of Markovian equations at leading order. The standard time-dependent perturbation theory in comparison is not capable of describing the non-linear condensate evolution beyond the early time regime of negligible damping. The macroscopic evolution of the condensate is interpreted in terms of microphysical particle processes. Our results have implications for the quantitative description of the decay of cosmological scalar fields in the early Universe, and may also be applied to other physical systems.
58 pages, 6 figures
References in corpus (17)
- Imperfect Dark Energy from Kinetic Gravity Braiding
- Reheating in Inflationary Cosmology: Theory and Applications
- Nonperturbative Dynamics Of Reheating After Inflation: A Review
- Warm Inflation and its Microphysical Basis
- Non-thermal fixed points: effective weak-coupling for strongly correlated systems far from equilibrium
- Primordial Curvature Fluctuation and Its Non-Gaussianity in Models with Modulated Reheating
- Inflation and the Scale Dependent Spectral Index: Prospects and Strategies
- Dynamics of oscillating scalar field in thermal environment
- Scalaron the mighty: producing dark matter and baryon asymmetry at reheating
- CMB constraints on the inflaton couplings and reheating temperature in -attractor inflation
- Dissipative Effects on Reheating after Inflation
- Systematic approach to thermal leptogenesis
- Particle production and reheating in the inflationary universe
- Local Approximations for Effective Scalar Field Equations of Motion
- On finite density effects on cosmic reheating and moduli decay and implications for Dark Matter production
- Quantum kinetic theory for fermions in temporally varying backrounds
- Challenges for Inflaton Dark Matter