Adiabaticity and the Fate of Non-Gaussianities: The Trispectrum and Beyond

Abstract

Extending the analysis of [1011.4934] beyond the bispectrum, we explore the superhorizon generation of local non-gaussianities and their subsequent approach to adiabaticity. Working with a class of two field models of inflation with potentials amenable to treatment with the delta N formalism we find that, as is the case for f_{NL}^{local}, the local trispectrum parameters tau_{NL} and g_{NL} are exponentially driven toward values which are slow roll suppressed if the fluctuations are driven into an adiabatic mode by a phase of effectively single field inflation. We argue that general considerations should ensure that a similar behavior will hold for the local forms of higher point correlations as well.

v3: Updated to match published version, minor corrections throughout, 17 pages; v2: Corrected counting of higher order non-linearity parameters, added references, updated formatting, conclusions unchanged, 16 pages; v1: 16 pages

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Cited by in corpus (16)

• Evolution of fNL to the adiabatic limit
• A Statistical Approach to Multifield Inflation: Many-field Perturbations Beyond Slow Roll
• Inflationary perturbation theory is geometrical optics in phase space
• Perturbative Reheating After Multiple-Field Inflation: The Impact on Primordial Observables
• On reaching the adiabatic limit in multi-field inflation
• Reheating, Multifield Inflation and the Fate of the Primordial Observables
• Large trispectrum in two-field slow-roll inflation
• Local non-Gaussianity from rapidly varying sound speeds
• Primordial curvature perturbation during and at the end of multi-field inflation
• δN versus covariant perturbative approach to non-Gaussianity outside the horizon in multifield inflation
• Effect of reheating on predictions following multiple-field inflation
• Non-Gaussianities in multi-field DBI inflation with a waterfall phase transition
• Influence of Reheating on the Trispectrum and its Scale Dependence
• Mixed non-Gaussianity in multiple-DBI inflation
• Extension of local-type inequality for the higher order correlation functions
• Observable predictions of generalised inflationary scenarios