Radion dynamics in multibrane Randall-Sundrum model

TL;DR

This paper investigates the behavior of the radion field in a multibrane Randall-Sundrum setup, demonstrating that effective field theory matches Einstein equations and confirming the radion's unique role after stabilization.

Contribution

It extends the analysis of radion dynamics to models with intermediate branes, validating EFT formalism and clarifying radion properties post-stabilization.

Findings

EFT equations match linearized Einstein equations with junction conditions

Radion remains a unique physical degree of freedom after stabilization

Goldberger-Wise mechanism stabilizes the radion in multibrane scenarios

Abstract

The radion in the Randall-Sundrum model is stabilized by the back reaction of a bulk scalar field with its VEV depending on the fifth dimensional coordinate. We studied the radion dynamics in an extended scenario, where intermediate branes exist between the UV and IR branes. Our analysis proves that the formalism of EFT delivers the same equations of motion as the linearized Einstein equation with all junction conditions satisfied. The relic of 5d diffeomorphism is broken after including the Goldberger-Wise stabilization and a unique radion field is conjectured as legitimate in the RS metric perturbation.