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.Comment: 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 page