Scale-dependent non-Gaussianity probes inflationary physics

Abstract

We calculate the scale dependence of the bispectrum and trispectrum in (quasi) local models of non-Gaussian primordial density perturbations, and characterize this scale dependence in terms of new observable parameters. They can help to discriminate between models of inflation, since they are sensitive to properties of the inflationary physics that are not probed by the standard observables. We find consistency relations between these parameters in certain classes of models. We apply our results to a scenario of modulated reheating, showing that the scale dependence of non-Gaussianity can be significant. We also discuss the scale dependence of the bispectrum and trispectrum, in cases where one varies the shape as well as the overall scale of the figure under consideration. We conclude providing a formulation of the curvature perturbation in real space, which generalises the standard local form by dropping the assumption that f_NL and g_NL are constants.

27 pages, 2 figures. v2: Minor changes to match the published version

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Cited by in corpus (10)

• On Classification of Models of Large Local-Type Non-Gaussianity
• Strongly Scale-dependent Non-Gaussianity
• Scale-Dependent Non-Gaussianity as a Generalization of the Local Model
• Non-Gaussianity in single field models without slow-roll
• Negative spectral index of $f_{NL}$ in the axion-type curvaton model
• Non-Gaussianity and Gravitational Waves from Quadratic and Self-interacting Curvaton
• Tilt and Running of Cosmological Observables in Generalized Single-Field Inflation
• Scale dependence of $f_{NL}$ in N-flation
• Non-Gaussianity and gravitational wave background in curvaton with a double well potential
• New features in curvaton model