Primordial non-Gaussianity as a signature of pre-inflationary radiation era

TL;DR

This paper investigates how a pre-inflationary radiation era influences primordial non-Gaussianities, revealing enhancements in bispectrum and trispectrum signals, with the trispectrum notably larger than the bispectrum.

Contribution

It demonstrates that a pre-inflationary radiation era amplifies non-Gaussianities, especially making the trispectrum larger than the bispectrum, which is a distinctive feature.

Findings

Both bispectrum and trispectrum non-Gaussianities are enhanced.

The trispectrum non-Gaussianity exceeds the bispectrum.

Pre-inflationary radiation era leaves a detectable imprint on primordial signals.

Abstract

Primordial non-Gaussianity generated in an inflationary model where inflation is preceded by a radiation era is discussed. It is shown that both bispectrum and trispectrum non-Gaussianities are enhanced due to the presence of pre-inflationary radiation era. One distinguishing feature of such a scenario is that the trispectrum non-Gaussianity is larger than the bispectrum one.