Non-Gaussianity and large-scale structure in a two-field inflationary model

TL;DR

This paper investigates how a two-field inflationary model with inflaton and curvaton contributions affects non-Gaussianity in the cosmic microwave background and large-scale structure, revealing large-scale stochasticity and constraining model parameters.

Contribution

It introduces the impact of combined inflaton and curvaton effects on non-Gaussianity and large-scale stochasticity, providing joint observational constraints.

Findings

Enhanced galaxy bias on large scales due to non-Gaussianity

Detection of large-scale stochasticity in the model

Constraints on non-Gaussianity parameter and perturbation ratio

Abstract

Single field inflationary models predict nearly Gaussian initial conditions and hence a detection of non-Gaussianity would be a signature of the more complex inflationary scenarios. In this paper we study the effect on the cosmic microwave background and on large scale structure from primordial non-Gaussianity in a two-field inflationary model in which both the inflaton and curvaton contribute to the density perturbations. We show that in addition to the previously described enhancement of the galaxy bias on large scales, this setup results in large-scale stochasticity. We provide joint constraints on the local non-Gaussianity parameter $\tilde f_{\rm NL}$ and the ratio $\xi$ of the amplitude of primordial perturbations due to the inflaton and curvaton using WMAP and SDSS data.