Primordial non-Gaussianity in noncanonical warm inflation

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 analyse 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 effect can be observed. We take the Dirac-Born-Infeld (DBI) inflation as a concrete example to find how the sound speed and the thermal dissipation strength to decide the non-Gaussianity and to get a lower bound of the sound speed constrained by PLANCK.

7 pages, 2 figures

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Cited by in corpus (8)

• The warm inflation story
• Warm inflation with non-comoving scalar field and radiation fluid
• Observational Constraints on Two-field Warm Inflation
• Consistency of a kind of general noncanonical warm inflation
• Non-Gaussianity in a general kind noncanonical warm inflation
• Primordial non-Gaussianity in noncanonical warm inflation: three- and four-point correlations
• Eckart heat-flux applicability in $F(\Phi ,X)R$ theories and the existence of temperature gradients
• Primordial non-Gaussianity in noncanonical warm inflation with nonminimal derivative coupling