Effects of Radiation on Primordial Non-Gaussianity

TL;DR

This paper investigates how a pre-inflationary radiation era influences non-Gaussian features in single-field slow-roll inflation, revealing enhanced bispectrum and trispectrum signals that could serve as observational signatures.

Contribution

It demonstrates that a radiation era before inflation enhances non-Gaussianities, with the trispectrum independent of slow-roll parameters, highlighting a novel observational signature.

Findings

Both bispectrum and trispectrum are enhanced in this scenario.

The trispectrum's amplitude is independent of slow-roll parameters.

The model predicts $ au_{NL}$ exceeds $f_{NL}$, indicating a distinctive non-Gaussian signature.

Abstract

We study the non-Gaussian features in single-field slow-roll inflationary scenario where inflation is preceded by a radiation era. In such a scenario both bispectrum and trispectrum non-Gaussianities are enhanced. Interestingly, the trispectrum in this scenario does not depend up on the slow-roll parameters and thus $\tau_{NL}$ is larger than $f_{NL}$ which can be a signature of such a pre-inflationary radiation era.