3-form inflation in Randall-Sundrum II

TL;DR

This paper investigates how a 3-form field driving inflation behaves in a five-dimensional Randall-Sundrum II braneworld, comparing it to four-dimensional models and analyzing observational constraints from Planck 2015 data.

Contribution

It extends 3-form inflation models to a Randall-Sundrum II braneworld scenario, analyzing the effects of the extra dimension on inflationary predictions.

Findings

Bulk effects modify spectral index and tensor-to-scalar ratio.

Constraints on model parameters are derived from Planck 2015 data.

Comparison with four-dimensional case highlights the influence of the extra dimension.

Abstract

It has been shown in the last few years that 3-form fields present viable cosmological solutions for inflation and dark energy with particular observable signatures distinct from those of canonical single scalar field inflation. The aim of this work is to explore the dynamics of a single 3-form in five dimensional Randall-Sundrum II braneworld scenario, in which a 3-form is confined to the brane and only gravity propagates in the bulk. We compare the solutions with the standard four dimensional case already studied in the literature. In particular, we evaluate how the spectral index and the ratio of tensor to scalar perturbations are influenced by the presence of the bulk and put constraints on the parameters of the models in the light of the recent Planck 2015 data.