Wave function of the radion in a brane world

TL;DR

This paper analyzes the radion's behavior in a two-brane Randall-Sundrum model and an infinite fifth dimension model, detailing its coupling strengths and properties through linearized metric perturbations.

Contribution

It provides a detailed calculation of the radion's linearized metric perturbation and coupling strengths in both finite and infinite extra dimension models.

Findings

Radion coupling strengths to matter on each brane are quantified.

Results agree with Garriga and Tanaka's analysis of gravitational forces.

Radion properties are characterized in models with infinite fifth dimension.

Abstract

We calculate the linearized metric perturbation corresponding to a massless four-dimensional scalar field, the radion, in a five-dimensional two-brane model of Randall and Sundrum. In this way we obtain relative strengths of the radion couplings to matter residing on each of the branes. The results are in agreement with the analysis of Garriga and Tanaka of gravitational and Brans--Dicke forces between matter on the branes. We also introduce a model with infinite fifth dimension and ``almost'' confined graviton, and calculate the radion properties in that model.