Non-Gaussianity in the modulated reheating scenario

By T. Suyama, Masahide Yamaguchi. 2007

253 citations recorded by the source corpus.

We investigate the non-Gaussianity of primordial curvature perturbations in the modulated reheating scenario where the primordial perturbation is generated due to the spatial fluctuation of the rate of the inflaton decay to radiation. We use the {delta}N formalism to evaluate the trispectrum of the curvature perturbation as well as its bispectrum. We give expressions for three nonlinear parameters f{sub NL}, {tau}{sub NL}, and g{sub NL} in the modulated reheating scenario. If both the intrinsic non-Gaussianity of scalar field fluctuations and third derivative of the decay rate with respect to the scalar fields are negligibly small, g{sub NL} has at least the same order of magnitude as f{sub NL}. We also give a general inequality between f{sub NL} and {tau}{sub NL}, which is true for other inflationary scenarios as long as the primordial non-Gaussianity comes from superhorizon evolution.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/344606743b44a9757cb1d7ede07b1a36aaf3654b

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Citations in the corpus

Cosmology and Fundamental Physics with the Euclid Satellite (2012, background): “Particularly interesting is the so-called Suyama-Yamaguchi inequality (e.g. Suyama & Yamaguchi 2008, Smith, LoVerde & Zaldarriaga 2011, Assassi, Baumann & Green 2012, Kehegias & Riotto 2012, Beltran Almeida, Rodriguez & Valenzuela-Toledo 2013) which connects the amplitudes of the bi- and…”
On soft limits of inflationary correlation functions (2012, methodology): “In that case one can show that the collapsed four-point function is always larger than the square of the squeezed three-point function [15].”
Inflation, Cosmic Perturbations and Non-Gaussianities (2013, background): “This scenario is known as the modulated reheating [117, 189, 190].”
Review of local non-Gaussianity from multi-field inflation (2010, background): “This inequality between τNL and fNL is true in general [75], and equality is reached whenever a single field direction during inflation generates the primordial curvature perturbation.”