Inflationary models inducing non-Gaussian metric fluctuations

TL;DR

These models are realizations of mechanisms in which non-Gaussianity is first generated by a light scalar field and then transferred into curvature fluctuations to construct explicit models of multi-field inflation in which the primordial metric fluctuations do not necessarily obey Gaussian statistics.

Abstract

We construct explicit models of multi-field inflation in which the primordial metric fluctuations do not necessarily obey Gaussian statistics. These models are realizations of mechanisms in which non-Gaussianity is first generated by a light scalar field and then transferred into curvature fluctuations. The probability distribution functions of the metric perturbation at the end of inflation are computed. This provides a guideline for designing strategies to search for non-Gaussian signals in future CMB and large scale structure surveys.

Figures (2)

• Figure 1: The shape of the probability distribution function of the isocurvature modes in case of a quartic coupling, \ref{['threefieldmodel']}, (solid line) compared to the analytic PDF of Eq. (\ref{['pdfapprox']}) (dashed line) and to Gaussian distribution (dotted line). In this example, $\lambda=10^{-2}$ and $N_e=50$.
• Figure 2: PDF for the two-field model with potential (\ref{['twofieldmodel1']}) at different timestep with the parameters (\ref{['para1']}-\ref{['parafin']}). The left panel describes the field trajectory and the shape of the wavepacket and the right panels compare the numerically obtained PDF (solid) to a Gaussian (dotted) and to the analytical PDF (\ref{['pdfapprox']}) (dash). $w$ is the effective equation of state parameter and $s_4$ is defined in Eq. (\ref{['kurtosis']}).