Dynamical Instabilities of the Randall-Sundrum Model

TL;DR

This paper investigates the stability of the Randall-Sundrum brane-world model, showing it is unstable under small perturbations and that scalar fields or fluids on the brane cannot cancel the bulk cosmological constant, impacting cosmological models.

Contribution

The paper derives dynamical equations for branes with matter and scalar fields, revealing the inherent instability of the Randall-Sundrum model under perturbations.

Findings

The model is unstable under small deviations from fine-tuning.

Scalar fields or fluids cannot cancel the bulk cosmological constant.

Implications for brane world cosmologies are discussed.

Abstract

We derive dynamical equations to describe a single 3-brane containing fluid matter and a scalar field coupling to the dilaton and the gravitational field in a five dimensional bulk. First, we show that a scalar field or an arbitrary fluid on the brane cannot evolve to cancel the cosmological constant in the bulk. Then we show that the Randall-Sundrum model is unstable under small deviations from the fine-tuning between the brane tension and the bulk cosmological constant and even under homogeneous gravitational perturbations. Implications for brane world cosmologies are discussed.