2012-04-23

Joe Elliston (Queen Mary)

Title: Large trispectrum from two-field slow-roll inflation

Abstract: We calculate the conditions required to produce an observable local trispectrum during two-field slow-roll inflation. This is done by extending and simplifying the ‘heatmap’ approach developed by Byrnes et al. The conditions required to generate a large trispectrum are broadly the same as those that can produce a large bispectrum. We derive a simple relation between tNL and fNL for models with separable potentials, and furthermore show that gNL and tNL can be related in specific circumstances. Additionally, we interpret the heatmaps dynamically, showing how they can be used as qualitative tools to understand the evolution of non-Gaussianity during inflation. We also show how fNL, tNL and gNL are sourced by different features in the inflationary potential, namely ridges, valleys and inflection points.