Inflationary Braneworld Driven By Bulk Scalar Field

TL;DR

This paper develops a formalism for inflation driven by a bulk scalar field in a braneworld scenario, deriving the effective 4D action and analyzing the role of dark components and Kaluza-Klein corrections.

Contribution

It introduces a new formalism to study bulk scalar field-driven inflation in two-brane systems, including effects of dark components and Kaluza-Klein corrections.

Findings

Inflation driven by bulk inflaton is feasible in the two-brane model.

Dark radiation and scalar sources are linked to the radion and vanish in the single-brane limit.

Kaluza-Klein corrections are incorporated into the inflationary analysis.

Abstract

We have developed a formalism to study an inflationary scenario driven by a bulk inflaton in the two-brane system. The 4-dimensional low energy effective action is obtained using the gradient expansion method. It is also found that the dark radiation and the dark scalar source are expressed by the radion. In the single-brane limit, we find these dark components disappear. Therefore, it turns out that the inflation due to the bulk inflaton successfully takes place. Kaluza-Klein corrections are also taken into account in this case.