Trispectrum estimator in equilateral type non-Gaussian models

Shuntaro Mizuno*, Kazuya Koyama



17 被引用数 (Scopus)


We investigate an estimator to measure the primordial trispectrum in equilateral type non-Gaussian models such as k-inflation, single field DBI inflation and multi-field DBI inflation models from Cosmic Microwave Background (CMB) anisotropies. The shape of the trispectrum whose amplitude is not constrained by the bispectrum in the context of effective theory of inflation and k-inflation is known to admit a separable form of the estimator for CMB anisotropies. We show that this shape is 87% correlated with the full quantum trispectrum in single field DBI inflation, while it is 33% correlated with the one in multi-field DBI inflation when curvature perturbation is originated from purely entropic contribution. This suggests that gNL equil,the amplitude of this particular shape, provides a reasonable measure of the non-Gaussianity from the trispectrum in equilateral non-Gaussian models. We relate model parameters such as the sound speed, cs and the transfer coefficient from entropy perturbations to the curvature perturbation, TRS with gNL equil, which enables us to constrain model parameters in these models once gNL equil is measured in WMAP and Planck.

ジャーナルJournal of Cosmology and Astroparticle Physics
出版ステータスPublished - 2010 10

ASJC Scopus subject areas

  • 天文学と天体物理学


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