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Title: De Sitter brane-world, localization of gravity, and the cosmological constant

Abstract

Cosmological models with a de Sitter 3-brane embedded in a 5-dimensional de Sitter spacetime (dS{sub 5}) give rise to a finite 4D Planck mass similar to that in Randall-Sundrum (RS) brane-world models in anti-de Sitter 5-dimensional spacetime(AdS{sub 5}). Yet, there arise a few important differences as compared to the results with a flat 3-brane or 4D Minkowski spacetime. For example, the mass reduction formula (MRF) M{sub Pl}{sup 2}=M{sub (5)}{sup 3}l{sub AdS} as well as the relationship M{sub Pl}{sup 2}=M{sub Pl(4+n)}{sup n+2}L{sup n} (with L being the average size or the radius of the n extra dimensions) expected in models of product-space (or Kaluza-Klein) compactifications get modified in cosmological backgrounds. In an expanding universe, a physically relevant MRF encodes information upon the 4-dimensional Hubble expansion parameter, in addition to the length and mass parameters L, M{sub Pl}, and M{sub Pl(4+n)}. If a bulk cosmological constant is present in the solution, then the reduction formula is further modified. With these new insights, we show that the localization of a massless 4D graviton as well as the mass hierarchy between M{sub Pl} and M{sub Pl(4+n)} can be explained in cosmological brane-world models. A notable advantage of having a 5D de Sitter bulk ismore » that in this case the zero-mass wave function is normalizable, which is not necessarily the case if the bulk spacetime is anti-de Sitter. In spacetime dimensions D{>=}7, however, the bulk cosmological constant {Lambda}{sub b} can take either sign ({Lambda}{sub b}<0, =0, or >0). The D=6 case is rather inconclusive, in which case {Lambda}{sub b} may be introduced together with 2-form gauge field (or flux). We obtain some interesting classical gravity solutions that compactify higher-dimensional spacetime to produce a Robertson-Walker universe with de Sitter-type expansion plus one extra noncompact direction. We also show that such models can admit both an effective 4-dimensional Newton constant that remains finite and a normalizable zero-mode graviton wave function.« less

Authors:
 [1]
  1. Department of Physics and Astronomy, University of Canterbury, Private Bag 4800, Christchurch 8041 (New Zealand)
Publication Date:
OSTI Identifier:
21541551
Resource Type:
Journal Article
Journal Name:
Physical Review. D, Particles Fields
Additional Journal Information:
Journal Volume: 83; Journal Issue: 8; Other Information: DOI: 10.1103/PhysRevD.83.086004; (c) 2011 American Institute of Physics; Journal ID: ISSN 0556-2821
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ANTI DE SITTER SPACE; BRANES; COMPACTIFICATION; COSMOLOGICAL CONSTANT; COSMOLOGICAL MODELS; DE SITTER SPACE; EXPANSION; GRAVITATION; KALUZA-KLEIN THEORY; MANY-DIMENSIONAL CALCULATIONS; MASS; MINKOWSKI SPACE; SPACE-TIME; UNIVERSE; WAVE FUNCTIONS; FIELD THEORIES; FUNCTIONS; MATHEMATICAL MODELS; MATHEMATICAL SPACE; SPACE; UNIFIED-FIELD THEORIES

Citation Formats

Neupane, Ishwaree P. De Sitter brane-world, localization of gravity, and the cosmological constant. United States: N. p., 2011. Web. doi:10.1103/PHYSREVD.83.086004.
Neupane, Ishwaree P. De Sitter brane-world, localization of gravity, and the cosmological constant. United States. doi:10.1103/PHYSREVD.83.086004.
Neupane, Ishwaree P. Fri . "De Sitter brane-world, localization of gravity, and the cosmological constant". United States. doi:10.1103/PHYSREVD.83.086004.
@article{osti_21541551,
title = {De Sitter brane-world, localization of gravity, and the cosmological constant},
author = {Neupane, Ishwaree P},
abstractNote = {Cosmological models with a de Sitter 3-brane embedded in a 5-dimensional de Sitter spacetime (dS{sub 5}) give rise to a finite 4D Planck mass similar to that in Randall-Sundrum (RS) brane-world models in anti-de Sitter 5-dimensional spacetime(AdS{sub 5}). Yet, there arise a few important differences as compared to the results with a flat 3-brane or 4D Minkowski spacetime. For example, the mass reduction formula (MRF) M{sub Pl}{sup 2}=M{sub (5)}{sup 3}l{sub AdS} as well as the relationship M{sub Pl}{sup 2}=M{sub Pl(4+n)}{sup n+2}L{sup n} (with L being the average size or the radius of the n extra dimensions) expected in models of product-space (or Kaluza-Klein) compactifications get modified in cosmological backgrounds. In an expanding universe, a physically relevant MRF encodes information upon the 4-dimensional Hubble expansion parameter, in addition to the length and mass parameters L, M{sub Pl}, and M{sub Pl(4+n)}. If a bulk cosmological constant is present in the solution, then the reduction formula is further modified. With these new insights, we show that the localization of a massless 4D graviton as well as the mass hierarchy between M{sub Pl} and M{sub Pl(4+n)} can be explained in cosmological brane-world models. A notable advantage of having a 5D de Sitter bulk is that in this case the zero-mass wave function is normalizable, which is not necessarily the case if the bulk spacetime is anti-de Sitter. In spacetime dimensions D{>=}7, however, the bulk cosmological constant {Lambda}{sub b} can take either sign ({Lambda}{sub b}<0, =0, or >0). The D=6 case is rather inconclusive, in which case {Lambda}{sub b} may be introduced together with 2-form gauge field (or flux). We obtain some interesting classical gravity solutions that compactify higher-dimensional spacetime to produce a Robertson-Walker universe with de Sitter-type expansion plus one extra noncompact direction. We also show that such models can admit both an effective 4-dimensional Newton constant that remains finite and a normalizable zero-mode graviton wave function.},
doi = {10.1103/PHYSREVD.83.086004},
journal = {Physical Review. D, Particles Fields},
issn = {0556-2821},
number = 8,
volume = 83,
place = {United States},
year = {2011},
month = {4}
}