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Supercurvaton

Vittoria Demozzi, Andrei Linde, Viatcheslav Mukhanov

TL;DR

This work embeds the curvaton scenario into a simple chaotic inflation model within supergravity, predicting that the local non-gaussianity $f_{NL}$ can naturally fall in the observable $O(10)$–$O(100)$ range and vary across the universe. By combining a broad supergravity-based inflationary class with stochastic and regime-by-regime analyses of the curvaton mass corrections, it demonstrates attractor behavior and identifies parameter regimes (notably through α and the mass scales) that yield sizable $f_{NL}$. It further shows that averaging over the curvaton web can significantly boost the ensemble-averaged $f_{NL}$ and that topological features (domain walls, strings, monopole-like structures) underpin large-local-$f_{NL}$ regions, with potential anthropic implications. The results offer a flexible framework for interpreting future CMB constraints and highlight the rich, non-perturbative landscape of curvaton-induced non-gaussianity in supergravity contexts.

Abstract

We discuss observational consequences of the curvaton scenario, which naturally appears in the context of the simplest model of chaotic inflation in supergravity. The non-gaussianity parameter f_NL in this scenario can take values in the observationally interesting range from O(10) to O(100). These values may be different in different parts of the universe. The regions where f_NL is particularly large form a curvaton web resembling a net of thick domain walls, strings, or global monopoles.

Supercurvaton

TL;DR

This work embeds the curvaton scenario into a simple chaotic inflation model within supergravity, predicting that the local non-gaussianity can naturally fall in the observable – range and vary across the universe. By combining a broad supergravity-based inflationary class with stochastic and regime-by-regime analyses of the curvaton mass corrections, it demonstrates attractor behavior and identifies parameter regimes (notably through α and the mass scales) that yield sizable . It further shows that averaging over the curvaton web can significantly boost the ensemble-averaged and that topological features (domain walls, strings, monopole-like structures) underpin large-local- regions, with potential anthropic implications. The results offer a flexible framework for interpreting future CMB constraints and highlight the rich, non-perturbative landscape of curvaton-induced non-gaussianity in supergravity contexts.

Abstract

We discuss observational consequences of the curvaton scenario, which naturally appears in the context of the simplest model of chaotic inflation in supergravity. The non-gaussianity parameter f_NL in this scenario can take values in the observationally interesting range from O(10) to O(100). These values may be different in different parts of the universe. The regions where f_NL is particularly large form a curvaton web resembling a net of thick domain walls, strings, or global monopoles.

Paper Structure

This paper contains 12 sections, 52 equations, 1 figure.

Table of Contents

  1. Introduction
  2. Curvaton scenario and chaotic inflation in supergravity
  3. Curvaton perturbations and non-gaussianity
  4. Stochastic approach
  5. Nongaussianity in various regimes
  6. A toy model with $m_{\sigma}^{2}=m^{2}$
  7. $m^2_{\sigma} = m^{2} +{\frac{9}{2}}H^{2}\sigma^{2}$
  8. $m^{2}_{\sigma} =m^{2}+\alpha H^{2},$ $\alpha >0$
  9. $m^2_{\sigma} = m^{2} +{\alpha} H^{2} +{\frac{9}{2}} H^{2}\sigma^{2}$, $\alpha > 0$
  10. $m^{2}_{\sigma} =m^{2}+ \alpha H^{2}+{\frac{9}{2}} H^{2}\sigma^{2}$, $\alpha < 0$
  11. Non-gaussianity and the curvaton web
  12. Discussion

Figures (1)

  • Figure 1: Behavior of the average value of the curvaton field $\sigma$ as a function of the inflaton field $\phi$, for various initial conditions. As we see, all trajectories which start at the early stages of inflation (large field $\phi$) converge to the same attractor solution. We follow it until the field $\phi$ becomes $O(1)$ and inflation ends. At large $\phi$, this solution is very close to the square root of the function (\ref{['funct']}), which is shown by the blue dashed line.