Phase space analysis of quintessence fields trapped in a Randall-Sundrum Braneworld: anisotropic Bianchi I brane with a Positive Dark Radiation term

TL;DR

This paper analyzes the dynamics of scalar fields in an anisotropic braneworld model with dark radiation, identifying conditions for stability and demonstrating that late-time de Sitter attractors are not favored in 5D-modified scenarios.

Contribution

It extends previous work by including anisotropy and dark radiation effects, providing new stability conditions for scalar field solutions in Randall-Sundrum braneworlds.

Findings

De Sitter solutions are saddle points in 5D-modified models.

Stable scalar field-matter and scalar field-dark radiation solutions are characterized.

Analytical results are illustrated with a simple toy model.

Abstract

In this paper we investigate, from the dynamical systems perspective, the evolution of an scalar field with arbitrary potential trapped in a Randall-Sundrum's Braneworld of type 2. We consider an homogeneous but anisotropic Bianchi I (BI) brane filled also with a perfect fluid. We also consider the effect of the projection of the five-dimensional Weyl tensor onto the three-brane in the form of a positive Dark Radiation term. Using the center manifold theory we obtain sufficient conditions for the asymptotic stability of de Sitter solution with standard 4D behavior. We also prove that there are not late time de Sitter attractors with 5D-modifications since they are always saddle-like. This fact correlates with a transient primordial inflation. We present here sufficient conditions on the potential for the stability of the scalar field-matter scaling solution, the scalar field-dominated solution, and the scalar field-dark radiation scaling solution. We illustrate our analytical findings using a simple $f$-deviser as a toy model. All these results are generalizations of our previous results obtained for FRW branes.