Consistency relations for sharp inflationary non-Gaussian features

TL;DR

This paper introduces a method to detect and analyze sharp inflationary features through the primordial non-Gaussian bispectrum alone, establishing consistency relations across different triangle configurations without relying on the power spectrum.

Contribution

It presents a novel approach to study inflationary features using only non-Gaussian bispectrum data, deriving relations that connect features across various configurations.

Findings

Features in non-Gaussian bispectrum are correlated across configurations.

Method enables detection of sharp inflationary features without power spectrum data.

Provides a new tool for analyzing inflationary physics through non-Gaussianity.

Abstract

If cosmic inflation suffered tiny time-dependent deviations from the slow-roll regime, these would induce the existence of small scale-dependent features imprinted in the primordial spectra, with their shapes and sizes revealing information about the physics that produced them. Small sharp features could be suppressed at the level of the two-point correlation function, making them undetectable in the power spectrum, but could be amplified at the level of the three-point correlation function, offering us a window of opportunity to uncover them in the non-Gaussian bispectrum. In this article, we show that sharp features may be analyzed using only data coming from the three point correlation function parametrizing primordial non-Gaussianity. More precisely, we show that if features appear in a particular non-Gaussian triangle configuration (e.g. equilateral, folded, squeezed), these must reappear in every other configuration according to a specific relation allowing us to correlate features across the non-Gaussian bispectrum. As a result, we offer a method to study scale-dependent features generated during inflation that depends only on data coming from measurements of non-Gaussianity, allowing us to omit data from the power spectrum.