Primordial non-Gaussianity in noncanonical warm inflation

2014/12/14 by Xiao-Min Zhang, Jian-Yang Zhu
Earth and Planetary Sciences · Physics and Astronomy · #Astronomy #Black Holes and Theoretical Physics #Cosmic microwave background #Cosmology and Gravitation Theories #Geophysics and Gravity Measurements #Inflation (cosmology) #Non-Gaussianity #Optics #Physics #Primordial fluctuations #gr-qc

paper · pdf · doi:10.1103/physrevd.91.063510

published as Phys. Rev. D 91, 063510 (2015) · 7 pages, 2 figures

arxiv created 2014/12/14 · openalex publication_date 2015/03/06 · arxiv updated 2015/04/09 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05

Abstract

We study the bispectrum of the primordial curvature perturbation on uniform density hypersurfaces generated by a kind of the noncanonical warm inflation, wherein the inflation is provided by a noncanonical scalar inflaton field that is coupled to radiation through a thermal dissipation effect. We obtain an analytic form for the nonlinear parameter f_NL that describes the non-Gaussianity in first-order cosmological perturbation theory and analyze the magnitude of this nonlinear parameter. We make a comparison between our result and those of the standard inflation and the canonical warm inflation. We also discuss when the contribution to the non-Gaussianity due to the second-order perturbation theory becomes more important and what the observations predict. We take the Dirac-Born-Infeld inflation as a concrete example to find how the sound speed and the thermal dissipation strength to decide the non-Gaussianity and get a lower bound of the sound speed constrained by Planck.

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