Adding Matter to Poincare Invariant Branes

TL;DR

This paper extends Poincare invariant brane models by incorporating matter, deriving new exact solutions with matter density and pressure, and analyzing their stability and cosmological implications.

Contribution

It introduces new exact static solutions with matter in branes and examines their stability, expanding previous models that lacked matter inclusion.

Findings

New static solutions with matter density and pressure

Instability of these solutions with respect to cosmological observations

Discovery of matterless static solutions and a unique non-static solution

Abstract

A solution to the cosmological constant problem has been proposed in which our universe is a 3-brane in a 5-dimensional spacetime. With a bulk scalar, the field equations admit a Poincare invariant brane solution regardless of the value of the cosmological constant (tension) on the brane. However, the solution does not include matter in the brane. We find new exact static solutions with matter density and pressure in the brane. We study small perturbations about these solutions. None seem consistent with observational cosmology. As a byproduct we find a class of new matterless static solutions and a non-static solution which, curiously, requires the string value for the dilaton coupling.