Inflation with a class of concave inflaton potentials in Randall\u2013Sundrum model

Ngo Phuc Duc Loc

doi:10.1140/epjc/s10052-020-8357-0

Abstract

We investigate inflation with a class of concave inflaton potentials of the form sim phi ^n(0<n<1) in the Randall–Sundrum model with an infinite extra spatial dimension. We show that this class of models is much more in good agreement with observations compared to the standard inflation. We also find the range of the five-dimensional Planck scale (M_5) and show that large tensor-to-scalar ratios do not eliminate small-field inflation in braneworld cosmology.

Highlights

The mysterious large mass hierarchy puzzle, which is the huge discrepancy between the Planck scale and the electroweak scale, has attracted many theoretical physicists in the late 20th century
Braneworld models are motivated from such a puzzle and they offer a simple solution by a realization of the existence of extra spatial dimension(s) [1,2,3]
It is interesting to see if this class is still valid in braneworld cosmology

Summary

Introduction

The mysterious large mass hierarchy puzzle, which is the huge discrepancy between the Planck scale and the electroweak scale, has attracted many theoretical physicists in the late 20th century. It addresses the profound question of why gravity is so weak. Braneworld models are motivated from such a puzzle and they offer a simple solution by a realization of the existence of extra spatial dimension(s) [1,2,3]. Primordial gravitational wave is the last important prediction which has not been confirmed yet. Future space-based gravitational wave detectors such as LISA may be able test this [5]. It is interesting to see if this class is still valid in braneworld cosmology

Inflation in Randall–Sundrum model

M56 4π M42

M56 16π 2

Conclusion