Deriving super-horizon curvature perturbations from the dynamics of preheating

TL;DR

This paper develops a framework to calculate super-horizon curvature perturbations from preheating dynamics, linking small-scale processes to large-scale cosmological observations, and estimates the non-Gaussianity generated.

Contribution

It introduces a novel analytical approach connecting preheating dynamics with curvature perturbations using Lyapunov theorem and $ abla N$ formulation, matching lattice results.

Findings

Analytical expression for super-horizon curvature perturbation

Estimated local non-Gaussianity from preheating

Connected preheating dynamics to CMB-scale perturbations

Abstract

We present a framework for calculating super-horizon curvature perturbation from the dynamics of preheating, which gives a reasonable match to the lattice results. Hubble patches with different initial background field values evolve differently. From the bifurcation of their evolution trajectories we find curvature perturbation using Lyapunov theorem and $\delta N$ formulation. In this way we have established a connection between the finer dynamics of preheating and the curvature perturbation produced in this era. From the calculated analytical form of the curvature perturbation we have derived the effective super-horizon curvature perturbation smoothed out on large scales of CMB. The order of the amount of local form non-gaussianity generated in this process has been calculated and problems regarding the precise determination of it have been pointed out.