2003/11/26 by Tsutomu Kobayashi, Takahiro Tanaka
Physics and Astronomy · #Black Holes and Theoretical Physics #Cosmology and Gravitation Theories #Galaxies: Formation, Evolution, Phenomena #gr-qc #hep-th
paper · pdf · doi:10.1103/physrevd.69.064037
published as Phys.Rev. D69 (2004) 064037 · 22 pages, 4 figures, revtex; v2: references added
arxiv created 2003/11/26 · openalex publication_date 2004/03/26 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We introduce a (5+m)\ensuremath-dimensional vacuum description of five-dimensional bulk inflaton models with exponential potentials that makes an analysis of cosmological perturbations simple and transparent. We show that various solutions, including the power-law inflation model recently discovered by Koyama and Takahashi, are generated from known (5+m)\ensuremath-dimensional vacuum solutions of pure gravity. We derive master equations for all types of perturbations, and each of them becomes a second order differential equation for one master variable supplemented by simple boundary conditions on the brane. One exception is the case for massive modes of scalar perturbations. In this case, there are two independent degrees of freedom, and in general it is difficult to disentangle them into two separate sectors.