Trispectrum estimator in equilateral type non-Gaussian models

Shuntaro Mizuno, Kazuya Koyama

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

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.

Original languageEnglish
Article number002
JournalJournal of Cosmology and Astroparticle Physics
Volume2010
Issue number10
DOIs
Publication statusPublished - 2010 Oct
Externally publishedYes

Keywords

  • Cosmological perturbation theory
  • Inflation
  • Non-gaussianity
  • String theory and cosmology

ASJC Scopus subject areas

  • Astronomy and Astrophysics

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