Abstract
We study cosmological perturbations in the brane models with an induced Einstein-Hilbert term on a brane. We consider an inflaton confined to a de Sitter brane in a five-dimensional Minkowski spacetime. Inflaton fluctuations excite Kaluza-Klein modes of bulk metric perturbations with mass m2 = -2(2ℓ-1)(ℓ+1)H2 and m2 = -2ℓ(2ℓ+3)H 2 where ℓ is an integer. There are two branches (± branches) of solutions for the background spacetime. In the + branch, which includes the self-accelerating universe, a resonance appears for a mode with m2 = 2H2 due to a spin-0 perturbation with m2 = 2H2. The self-accelerating universe has a distinct feature because there is also a helicity-0 mode of spin-2 perturbations with m2 = 2H2. In the - branch, which can be thought as the Randall-Sundrum type brane-world with the high energy quantum corrections, there is no resonance. At high energies, we analytically confirm that four-dimensional Einstein gravity is recovered, which is related to the disappearance of the van Dam-Veltman-Zakharov discontinuity in de Sitter spacetime. On sufficiently small scales, we confirm that the linearized gravity on the brane is well described by the Brans-Dicke theory with ω = 3Hrc in the - branch and ω = -3Hrc in the + branch, respectively, which confirms the existence of the ghost in the + branch. We also study large scale perturbations. In the + branch, the resonance induces a non-trivial anisotropic stress on the brane via the projection of the Weyl tensor in the bulk, but no instability is shown to exist on the brane.
| Original language | English |
|---|---|
| Article number | 013 |
| Journal | Journal of Cosmology and Astroparticle Physics |
| Issue number | 7 |
| DOIs | |
| Publication status | Published - 2006 Jul 1 |
| Externally published | Yes |
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Keywords
- Cosmological perturbation theory
- Cosmology with extra dimensions
- Inflation
ASJC Scopus subject areas
- Physics and Astronomy(all)
Cite this
Inflaton perturbations in brane-world cosmology with induced gravity. / Koyama, Kazuya; Mizuno, Shuntaro.
In: Journal of Cosmology and Astroparticle Physics, No. 7, 013, 01.07.2006.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Inflaton perturbations in brane-world cosmology with induced gravity
AU - Koyama, Kazuya
AU - Mizuno, Shuntaro
PY - 2006/7/1
Y1 - 2006/7/1
N2 - We study cosmological perturbations in the brane models with an induced Einstein-Hilbert term on a brane. We consider an inflaton confined to a de Sitter brane in a five-dimensional Minkowski spacetime. Inflaton fluctuations excite Kaluza-Klein modes of bulk metric perturbations with mass m2 = -2(2ℓ-1)(ℓ+1)H2 and m2 = -2ℓ(2ℓ+3)H 2 where ℓ is an integer. There are two branches (± branches) of solutions for the background spacetime. In the + branch, which includes the self-accelerating universe, a resonance appears for a mode with m2 = 2H2 due to a spin-0 perturbation with m2 = 2H2. The self-accelerating universe has a distinct feature because there is also a helicity-0 mode of spin-2 perturbations with m2 = 2H2. In the - branch, which can be thought as the Randall-Sundrum type brane-world with the high energy quantum corrections, there is no resonance. At high energies, we analytically confirm that four-dimensional Einstein gravity is recovered, which is related to the disappearance of the van Dam-Veltman-Zakharov discontinuity in de Sitter spacetime. On sufficiently small scales, we confirm that the linearized gravity on the brane is well described by the Brans-Dicke theory with ω = 3Hrc in the - branch and ω = -3Hrc in the + branch, respectively, which confirms the existence of the ghost in the + branch. We also study large scale perturbations. In the + branch, the resonance induces a non-trivial anisotropic stress on the brane via the projection of the Weyl tensor in the bulk, but no instability is shown to exist on the brane.
AB - We study cosmological perturbations in the brane models with an induced Einstein-Hilbert term on a brane. We consider an inflaton confined to a de Sitter brane in a five-dimensional Minkowski spacetime. Inflaton fluctuations excite Kaluza-Klein modes of bulk metric perturbations with mass m2 = -2(2ℓ-1)(ℓ+1)H2 and m2 = -2ℓ(2ℓ+3)H 2 where ℓ is an integer. There are two branches (± branches) of solutions for the background spacetime. In the + branch, which includes the self-accelerating universe, a resonance appears for a mode with m2 = 2H2 due to a spin-0 perturbation with m2 = 2H2. The self-accelerating universe has a distinct feature because there is also a helicity-0 mode of spin-2 perturbations with m2 = 2H2. In the - branch, which can be thought as the Randall-Sundrum type brane-world with the high energy quantum corrections, there is no resonance. At high energies, we analytically confirm that four-dimensional Einstein gravity is recovered, which is related to the disappearance of the van Dam-Veltman-Zakharov discontinuity in de Sitter spacetime. On sufficiently small scales, we confirm that the linearized gravity on the brane is well described by the Brans-Dicke theory with ω = 3Hrc in the - branch and ω = -3Hrc in the + branch, respectively, which confirms the existence of the ghost in the + branch. We also study large scale perturbations. In the + branch, the resonance induces a non-trivial anisotropic stress on the brane via the projection of the Weyl tensor in the bulk, but no instability is shown to exist on the brane.
KW - Cosmological perturbation theory
KW - Cosmology with extra dimensions
KW - Inflation
UR - http://www.scopus.com/inward/record.url?scp=42749108311&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=42749108311&partnerID=8YFLogxK
U2 - 10.1088/1475-7516/2006/07/013
DO - 10.1088/1475-7516/2006/07/013
M3 - Article
AN - SCOPUS:42749108311
JO - Journal of Cosmology and Astroparticle Physics
JF - Journal of Cosmology and Astroparticle Physics
SN - 1475-7516
IS - 7
M1 - 013
ER -