Cosmic vorticity on the brane
Abstract
We study vector perturbations about four-dimensional brane-world cosmologies embedded in a five-dimensional vacuum bulk. Even in the absence of matter perturbations, vector perturbations in the bulk metric can support vector metric perturbations on the brane. We show that during de Sitter inflation on the brane vector perturbations in the bulk obey the same wave equation for a massless five-dimensional field as found for tensor perturbations. However, we present the second-order effective action for vector perturbations and find no normalisable zero-mode in the absence of matter sources. The spectrum of normalisable states is a continuum of massive modes that remain in the vacuum state during inflation.
Cite
@article{arxiv.hep-th/0010133,
title = {Cosmic vorticity on the brane},
author = {Helen A. Bridgman and Karim A. Malik and David Wands},
journal= {arXiv preprint arXiv:hep-th/0010133},
year = {2009}
}
Comments
10 pages, latex with revtex. Expanded discussion of observational effects and minor corrections. Version to appear in Phys. Rev. D