Astronomy and Astrophysics – Astrophysics – General Relativity and Quantum Cosmology
Scientific paper
2003-03-27
Phys.Rev.D68:024016,2003
Astronomy and Astrophysics
Astrophysics
General Relativity and Quantum Cosmology
21 pages including 6 pages for several appendixes, no figures
Scientific paper
10.1103/PhysRevD.68.024016
We consider a braneworld inflation model driven by the dynamics of a scalar field living in the 5-dimensional bulk, the so-called ``bulk inflaton model'', and investigate the geometry in the bulk and large scale cosmological perturbations on the brane. The bulk gravitational effects on the brane are described by a projection of the 5-dimensional Weyl tensor, which we denote by $E_{\mu\nu}$. Focusing on a tachionic potential model, we take a perturbative approach in the anti-de Sitter (AdS$_5$) background with a single de Sitter brane. We first formulate the evolution equations for $E_{\mu\nu}$ in the bulk. Next, applying them to the case of a spatially homogeneous brane, we obtain two different integral expressions for $E_{\mu\nu}$. One of them reduces to the expression obtained previously when evaluated on the brane. The other is a new expression that may be useful for analyzing the bulk geometry. Then we consider superhorizon scale cosmological perturbations and evaluate the bulk effects onto the brane. In the limit $H^2\ell^2\ll1$, where $H$ is the Hubble parameter on the brane and $\ell$ is the bulk curvature radius, we find that the effective theory on the brane is identical to the 4-dimensional Einstein-scalar theory with a simple rescaling of the potential even under the presence of inhomogeneities. % atleast on super-Hubble horizon scales. In particular, it is found that the anticipated non-trivial bulk effect due to the spatially anisotropic part of $E_{\mu\nu}$ may appear only at %second order in the low energy expansion, i.e., at $O(H^4\ell^4)$.
Himemoto Yoshiaki
Minamitsuji Masato
Sasaki Misao
No associations
LandOfFree
Geometry and cosmological perturbations in the bulk inflaton model does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Geometry and cosmological perturbations in the bulk inflaton model, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Geometry and cosmological perturbations in the bulk inflaton model will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-132784