Non-Gaussian features from the inverse volume corrections in loop quantum cosmology

TL;DR

This paper investigates how inverse volume corrections in loop quantum cosmology influence non-Gaussian features of primordial fluctuations, revealing small increases in non-Gaussianity and the emergence of new bispectrum shapes.

Contribution

It provides the first detailed analysis of non-Gaussian features in loop quantum cosmology with inverse volume corrections, identifying new bispectrum shapes and quantifying their effects.

Findings

Loop quantum corrections increase $f_{NL}$ by 0.1%.

Two new bispectrum shapes $\\mathcal{F}_1$ and $\\mathcal{F}_2$ are identified.

Shape $\\mathcal{F}_1$ is less correlated with standard types, $\\mathcal{F}_2$ is highly correlated with local.

Abstract

In this paper we study the non-Gaussian features of the primordial fluctuations in loop quantum cosmology with the inverse volume corrections. The detailed analysis is performed in the single field slow-roll inflationary models. However, our results reflect the universal characteristics of bispectrum in loop quantum cosmology. The main corrections to the scalar bispectrum come from two aspects: one is the modifications to the standard Bunch-Davies vacuum, the other is the corrections to the background dependent variables, such as slow-roll parameters. Our calculations show that the loop quantum corrections make $f_{{\rm NL}}$ of the inflationary models increase 0.1%. Moreover, we find that two new shapes arise, namely $\mathcal F_{1}$ and $\mathcal F_{2}$. The former gives a unique loop quantum feature which is less correlated with the local, equilateral and single types, while the latter is highly correlated with the local one.