Braneworld Cosmology

TL;DR

This paper develops a formalism for inflation in two-brane models, deriving effective 4D equations and proposing a new braneworld inflation scenario, advancing theoretical understanding of early universe cosmology.

Contribution

It introduces a gradient expansion method and derives a 4D effective action for two-brane inflation models, providing new tools for braneworld cosmology analysis.

Findings

Derived effective 4D action for two-brane system

Formulated background and perturbation equations

Proposed a novel born-again braneworld inflation scenario

Abstract

We present a general formalism for studying an inflationary scenario in the two-brane system. We explain the gradient expansion method and obtain the 4-dimensional effective action. Based on this effective action, we give a basic equations for the background homogeneous universe and the cosmological perturbations. As an application, we propose a born-again braneworld scenario.