BICEP's bispectrum

TL;DR

This paper explores how inflationary models consistent with Bicep2 results predict a significant increase in large-scale non-Gaussianity, indicating potential observational signatures beyond simple power spectrum suppression.

Contribution

It demonstrates that inflationary trajectories favored by Bicep2 data also produce substantially larger non-Gaussian signals at large scales.

Findings

Large-scale non-Gaussianity is an order of magnitude higher than standard models.

Bicep2-favored inflationary models predict enhanced non-Gaussian signals.

Scalar power spectrum suppression correlates with increased non-Gaussianity.

Abstract

The simplest interpretation of the Bicep2 result is that the scalar primordial power spectrum is slightly suppressed at large scales. These models result in a large tensor-to-scalar ratio $r$. In this work we show that the type of inflationary trajectory favoured by Bicep2 also leads to a larger non-Gaussian signal at large scales, roughly an order of magnitude larger than a standard slow-roll trajectory.