Scalar Perturbation Produced at the Pre-inflationary Stage in Eddington-inspired Born-Infeld Gravity

TL;DR

This paper studies scalar perturbations in Eddington-inspired Born-Infeld gravity during pre-inflation, revealing a rise in power spectrum at low modes and a reduced tensor-to-scalar ratio, impacting gravitational wave detection debates.

Contribution

It introduces a novel analysis of scalar perturbations in Eddington-inspired Born-Infeld gravity during pre-inflation, highlighting unique spectral features and implications for gravitational wave observations.

Findings

Scalar power spectrum rises at low k-modes.

Tensor-to-scalar ratio is significantly lowered.

Results impact interpretations of gravitational wave data.

Abstract

We investigate the scalar perturbation produced at the pre-inflationary stage driven by a massive scalar field in Eddington-inspired Born-Infeld gravity. The scalar power spectrum exhibits a peculiar rise for low $k$-modes. The tensor-to-scalar ratio can be significantly lowered compared with that in the standard chaotic inflation model in general relativity. This result is very affirmative considering the recent dispute on the detection of the gravitational wave radiation between PLANCK and BICEP2.