Primordial non-Gaussianity from the DBI Galileons

Shuntaro Mizuno, Kazuya Koyama

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Abstract

We study primordial fluctuations generated during inflation in a class of models motivated by the DBI Galileons, which are extensions of the DBI action that yield second-order field equations. This class of models generalizes the DBI Galileons in a similar way with K inflation. We calculate the primordial non-Gaussianity from the bispectrum of the curvature perturbations at leading order in the slow-varying approximations. We show that the estimator for the equilateral-type non-Gaussianity, fNLequil, can be applied to measure the amplitude of the primordial bispectrum even in the presence of the Galileon-like term although it gives a slightly different momentum dependence from K-inflation models. For the DBI Galileons, we find -0.32/cs2
Original languageEnglish
Pages (from-to)103518
Number of pages1
JournalPhysical Review D
Volume82
Issue number10
DOIs
Publication statusPublished - 12 Nov 2010

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