Numerical evaluation of the tensor bispectrum in two field inflation

TL;DR

This paper numerically evaluates the tensor bispectrum parameter in two-field inflation models, compares results with slow roll approximations, and explores effects of field space curvature, preheating, and the squeezed limit consistency relation.

Contribution

It provides a detailed numerical analysis of the tensor bispectrum in various two-field inflation models, including effects of curved trajectories and preheating.

Findings

Numerical values of $h_{NL}$ for different models.

Validation of the tensor bispectrum consistency relation.

Impact of preheating on tensor non-Gaussianity.

Abstract

We evaluate the dimensionless non-Gaussianity parameter $h_{_{\rm NL}}$, that characterizes the amplitude of the tensor bispectrum, numerically for a class of two field inflationary models such as double inflation, hybrid inflation and aligned natural inflation. We compare the numerical results with the slow roll results which can be obtained analytically. In the context of double inflation, we also investigate the effects on $h_{_{\rm NL}}$ due to curved trajectories in the field space. We explicitly examine the validity of the consistency relation governing the tensor bispectrum in the squeezed limit. Lastly, we discuss the contribution to $h_{_{\rm NL}}$ due to the epoch of preheating in two field models.