A four-dimensional description of five-dimensional N-brane models

TL;DR

This paper introduces a new, efficient method to derive four-dimensional effective gravity theories from five-dimensional braneworld models with multiple branes, focusing on radion modes and applicable to various model configurations.

Contribution

It presents a novel two-lengthscale expansion approach for deriving effective theories in multi-brane models, emphasizing radion dynamics and simplifying the analysis of complex extra-dimensional setups.

Findings

Radion modes form a (N-1)-dimensional nonlinear sigma model.

Method is straightforward, computationally efficient, and applicable to both compactified and uncompactified models.

Illustrated with an N-brane model in an uncompactified extra dimension.

Abstract

We propose a new method for obtaining the four-dimensional effective gravitational theory for five-dimensional braneworld models with arbitrary numbers of branes in a low energy regime, based on a two-lengthscale expansion. The method is straightforward and computationally efficient, and is applicable to both compactified and uncompactified models. Particular emphasis is placed on the behavior of the radion modes of the model, while the massive effective fields are automatically truncated. Generally, the radion modes are found to form a (N-1)-dimensional nonlinear sigma model. We illustrate the method for a N-brane model in an uncompactified extra dimension.