Regular braneworlds with nonlinear bulk-fluids

TL;DR

This paper constructs a smooth five-dimensional brane-world model with localized gravity, featuring a nonlinear bulk fluid that satisfies energy conditions and results in a finite four-dimensional Planck mass.

Contribution

It introduces a regular brane-world setup with nonlinear bulk fluids, ensuring non-singular geometry and finite Planck mass, advancing the understanding of higher-dimensional gravity models.

Findings

Geometry is free of singularities within finite distance from the brane.

Null energy condition is satisfied for specific parameter ranges.

Induced four-dimensional Planck mass is finite.

Abstract

We construct a regular five-dimensional brane-world with localised gravity on a flat 3-brane. The matter content in the bulk is parametrised by an analog of a non-linear fluid with equation of state $p=\gamma\rho^\lambda$ between the `pressure' $p$ and the `density' $\rho$ dependent on the 5th dimension. For $\gamma$ negative and $\lambda>1$, the null energy condition is satisfied, and the geometry is free of singularities within finite distance from the brane, while the induced four-dimensional Planck mass is finite.