Large trispectrum in two-field slow-roll inflation

We calculate the conditions required to produce a large local trispectrum during two-field slow-roll inflation. This is done by extending and simplifying the 'heat-map' approach developed by Byrnes et a l. 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 tau(NL) and f(NL) for models with separable potentials, and furthermore show that g(NL) and tau(NL) 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 f(NL), tau(NL) and g(NL) are sourced by generic shapes in the inflationary potential, namely ridges, valleys and infection points.