Non-Gaussianity after BICEP2

TL;DR

This paper investigates the potential for detectable non-Gaussianity in single-field inflation models with large tensor-to-scalar ratios, providing sharp predictions that can be tested by future observations.

Contribution

It demonstrates that significant non-Gaussianity can exist in simple inflation models with large tensor ratios, with tightly constrained shapes.

Findings

Detectable non-Gaussianity ($f_{NL} \, \sim \, 50$) is possible in simple models.

The shape of non-Gaussianity is tightly constrained, enabling clear observational tests.

Future detection or falsification of non-Gaussianity can confirm or challenge these models.

Abstract

We analyze primordial non-Gaussianity in single field inflationary models when the tensor/scalar ratio is large. Our results show that detectable levels of non-Gaussianity $f_{NL} \sim 50$ are still possible in the simplest class of models described by the effective theory of inflation. However, the shape is very tightly constrained, making a sharp prediction that could be confirmed or falsified by a future detection of non-Gaussianity.