Behavior of Cosmological Perturbations in the Brane-World Mode

Abstract

In this paper we present a gauge-invariant formalism for perturbations of the brane-world model developed by the author, A. Ishibashi and O. Seto recently, and analyze the behavior of cosmological perturbations in a spatially flat expanding universe realized as a boundary 3-brane in AdS${}^5$ in terms of this formalism. For simplicity we restrict arguments to scalar perturbations. We show that the behavior of cosmological perturbations on superhorizon scales in the brane-world model is the same as that in the standard no-extradimension model, irrespective of the initial condition for bulk perturbations, in the late stage when the cosmic expansion rate $H$ is smaller than the inverse of the bulk curvature scale $\ell$. Further, we give rough estimates which indicate that in the early universe when $H$ is much larger than $1/\ell$, perturbations in these two models behave quite differently, and the conservation of the Bardeen parameter does not hold for superhorizon perturbations in the brane-world model.

4 pages in the revtex style. A talk in the conference CAPP2000 to be published in the proceedings

Cited by in corpus (6)

• Modified Gravity and Cosmology
• Brane-World Gravity
• Testing General Relativity in Cosmology
• Late time behavior of cosmological perturbations in a single brane model
• Cosmological perturbations of an expanding brane in an anti-de Sitter bulk: a short review
• Spin-Torsion, Braneworlds and Changing Symmetry in the Universe