Forethought on the Environmental Situation in 21st Century

Nihei, Yoshimasa

doi:10.5363/tits.4.11_81

Cited by 34 publications

(68 citation statements)

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“…Although we have no analytical proof, the above results, together with some numerical examples we have checked, strongly indicate that the slow-roll solution exists for all possible values of κ 33) it is expressed exactly as…”

Section: φ(T R) = ψ(T) U(r) (313)mentioning

confidence: 79%

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Brane-world inflation without inflaton on the brane

2001

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Inspired by the Randall-Sundrum brane-world scenario, we investigate the possibility of braneworld inflation driven not by an inflaton field on the brane, but by a bulk, dilaton-like gravitational field. As a toy model for the dilaton-like gravitational field, we consider a minimally coupled massive scalar field in the bulk 5-dimensional spacetime, and look for a perturbative solution in the anti-de Sitter (AdS) background. For an adequate range of the scalar field mass, we find a unique solution that has non-trivial dependence on the 5th dimensional coordinate and that induces slow-roll inflation on the brane.

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Section: φ(T R) = ψ(T) U(r) (313)mentioning

confidence: 79%

“…The formulation and evolution of cosmological perturbations in the brane-world are discussed in [18][19][20]23,25]. And inflation on the brane is discussed by many people [26][27][28][30][31][32][33][34][35][36][37][38].…”

Section: Introductionmentioning

confidence: 99%

Brane-world inflation without inflaton on the brane

2001

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“…It turns out that in order to do so, one must extract a factor ie pπ / sinh p ′ π from its coefficient functions 15 . We denote the final form of the bitensor by…”

Section: Lorentzian Correlatormentioning

confidence: 99%

Brane new world

2000

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We study a Randall-Sundrum cosmological scenario consisting of a domain wall in anti-de Sitter space with a strongly coupled large N conformal field theory living on the wall. The AdS/CFT correspondence allows a fully quantum mechanical treatment of this CFT, in contrast with the usual treatment of matter fields in inflationary cosmology. The conformal anomaly of the CFT provides an effective tension which leads to a de Sitter geometry for the domain wall. This is the analogue of Starobinsky's four dimensional model of anomaly driven inflation. Studying this model in a Euclidean setting gives a natural choice of boundary conditions at the horizon. We calculate the graviton correlator using the Hartle-Hawking "No Boundary" proposal and analytically continue to Lorentzian signature. We find that the CFT strongly suppresses metric perturbations on all but the largest angular scales. This is true independently of how the de Sitter geometry arises, i.e., it is also true for four dimensional Einstein gravity. Since generic matter would be expected to behave like a CFT on small scales, our results suggest that tensor perturbations on small scales are far smaller than predicted by all previous calculations, which have neglected the effects of matter on tensor perturbations.

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“…On the other hand, several authors have obtained in-flationary solutions for the three-brane worlds with nontrivial configurations in the extra dimension [11,[14][15][16]. Most of such solutions are based on imposing different absolute values for the tensions of the two branes, taking the resulting neat tension as the source of the exponential expansion [15].…”

Section: Introductionmentioning

confidence: 99%

“…Most of such solutions are based on imposing different absolute values for the tensions of the two branes, taking the resulting neat tension as the source of the exponential expansion [15]. Of course, the implicit main aim of all these inflationary brane models is at solving standard cosmological puzzles such as horizon and flatness problems.…”

Section: Introductionmentioning

confidence: 99%

Cosmological Predictions From the Misner Brane

González-Dı́az

2003

Int. J. Mod. Phys. D

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Within the spirit of five-dimensional gravity in the Randall-Sundrum scenario, in this paper we consider cosmological and gravitational implications induced by forcing the spacetime metric to satisfy a Misner-like symmetry. We first show that in the resulting Misner-brane framework the Friedmann metric for a radiation dominated flat universe and the Schwarzschild or anti-de Sitter black hole metrics are exact solutions on the branes, but the model cannot accommodate any inflationary solution. The horizon and flatness problems can however be solved in Misner-brane cosmology by causal and noncausal communications through the extra dimension between distant regions which are outside the horizon. Based on a semiclassical approximation to the path-integral approach, we have calculated the quantum state of the Misner-brane universe and the quantum perturbations induced on its metric by brane propagation along the fifth direction. We have then considered testable predictions from our model. These include a scale-invariant spectrum of density perturbations whose amplitude can be naturally accommodated to the required value 10 −5 -10 −6 , and a power spectrum of CMB anisotropies whose acoustic peaks are at the same sky angles as those predicted by inflationary models, but having much smaller secondary-peak intensities. These predictions seem to be compatible with COBE and recent Boomerang and Maxima measurements.

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Forethought on the Environmental Situation in 21st Century

Cited by 34 publications

References 0 publications

Brane-world inflation without inflaton on the brane

Brane-world inflation without inflaton on the brane

Brane new world

Cosmological Predictions From the Misner Brane

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