Nonlinear dynamics of oscillons and transients during preheating after single field inflation

TL;DR

This paper investigates the nonlinear dynamics during preheating after single-field inflation, focusing on how potential parameters influence resonance and structure formation in various inflation models.

Contribution

It provides a comparative analysis of nonlinear structures and energy transfer in $eta$-attractor and monodromy models, highlighting the dominant role of small-field parameters.

Findings

Resonance bands are significantly affected by monodromy model parameters.

Nonlinear dynamics are similar across different inflation models.

Small-field parameter $n$ has a major impact on nonlinear behavior.

Abstract

In the single-field model, the preheating process occurs through self-resonance of inflaton field. We study the nonlinear structures generated during preheating in the $\alpha$-attractor models and monodromy models. The potentials have a power law form $\propto\left|\phi\right|^{2n}$ near the origin and a flat region away from bottom, which are consistent with current cosmological observations. The Floquet analysis shows that potential parameters in monodromy model have a significant influence on the region of resonance bands. Besides we investigate the formation of nonlinear structures, the equation of state and the energy transfer through the (3+1) dimensional lattice simulation. We find that all the models exhibit similar nonlinear dynamics. Furthermore, our analysis reveals that the behavior of the inflation model at small field values, which is governed by the parameter $n$, exerts a more substantial influence on the nonlinear dynamics. The behavior at large field values, controlled by the parameter $q$, has a negligible impact.