Inflation in the five-dimensional universe with an orbifold extra dimension

Nihei, Takeshi

doi:10.1016/s0370-2693(99)01085-0

Cited by 211 publications

(127 citation statements)

References 12 publications

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“…(2). Our boundary conditions are found by considering the two 3-branes at u = 0 and u = l. These are the planes at which we have discontinuities in the normal derivatives of the metric, and hence where the Israel conditions for the boundaries give nontrivial constraints.…”

Section: Israel Conditions For Our Modelmentioning

confidence: 99%

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Cosmological challenges in theories with extra dimensions and remarks on the horizon problem

1999

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We consider the cosmology that results if our observable universe is a 3-brane in a higher dimensional universe. In particular, we focus on the case where our 3-brane is located at the Z2 symmetry fixed plane of a Z2 symmetric five-dimensional spacetime, as in the Hořava-Witten model compactified on a Calabi-Yau manifold. As our first result, we find that there can be substantial modifications to the standard Friedmann-Robertson-Walker (FRW) cosmology; as a consequence, a large class of such models is observationally inconsistent. In particular, any relationship between the Hubble constant and the energy density on our brane is possible, including (but not only) FRW. Generically, due to the existence of the bulk and the boundary conditions on the orbifold fixed plane, the relationship is not FRW, and hence cosmological constraints coming from big bang nucleosynthesis, structure formation, and the age of the universe difficult to satisfy. We do wish to point out, however, that some specific choices for the bulk stress-energy tensor components do reproduce normal FRW cosmology on our brane, and we have constructed an explicit example. As our second result, for a broad class of models, we find a somewhat surprising fact: the stabilization of the radius of the extra dimension and hence the four dimensional Planck mass requires unrealistic fine-tuning of the equation of state on our 3-brane. In the last third of the paper, we make remarks about causality and the horizon problem that apply to any theory in which the volume of the extra dimension determines the four-dimensional gravitational coupling. We point out that some of the assumptions that lead to the usual inflationary requirements are modified.98.80, 98.80.C

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Section: Israel Conditions For Our Modelmentioning

confidence: 99%

“…There has been additional study of cosmology in scenarios without a Z 2 symmetry. References of previous cosmological work in the context of our observable universe as a 3-brane in a higher dimensional context include [2][3][4].…”

Section: Introductionmentioning

confidence: 99%

Cosmological challenges in theories with extra dimensions and remarks on the horizon problem

1999

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“…Few such candidates are -supersymmetry, technicolor and extra dimensions. Among many such attempts [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15], RandallSundrum (RS) model [6] of warped extra dimension draws special attention since it resolves the gauge hierarchy problem without choosing any intermediate scale in the theory.…”

Section: Introductionmentioning

confidence: 99%

Radion stabilization in higher curvature warped spacetime

et al. 2018

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We consider a five dimensional AdS spacetime in presence of higher curvature term like F(R) = R + α R 2 in the bulk. In this model, we examine the possibility of modulus stabilization from the scalar degrees of freedom of higher curvature gravity free of ghosts. Our result reveals that the model stabilizes itself and the mechanism of modulus stabilization can be argued from a geometric point of view. We determine the region of the parametric space for which the modulus (or radion) can to be stabilized. We also show how the mass and coupling parameters of radion field are modified due to higher curvature term leading to modifications of its phenomenological implications on the visible 3-brane.

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“…Over the last two decades models with extra spatial dimensions [1][2][3][4][5][6][7][8][9][10][11][12][13] have been increasingly playing a central role in physics beyond the standard models of particles [14] and cosmology [15][16][17]. Such higher dimensional scenarios occur naturally in string theory.…”

Section: Introductionmentioning

confidence: 99%

Fermion localization in higher curvature and scalar–tensor theories of gravity

Mitra¹,

Paul

SenGupta

2017

Eur. Phys. J. C

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It is well known that, in a braneworld model, the localization of fermions on a lower dimensional submanifold (say a TeV 3-brane) is governed by the gravity in the bulk, which also determines the corresponding phenomenology on the brane. Here we consider a five dimensional warped spacetime where the bulk geometry is governed by higher curvature like F(R) gravity. In such a scenario, we explore the role of higher curvature terms on the localization of bulk fermions which in turn determines the effective radion-fermion coupling on the brane. Our result reveals that, for appropriate choices of the higher curvature parameter, the profiles of the massless chiral modes of the fermions may get localized near the TeV brane, while those for massive Kaluza-Klein (KK) fermions localize towards the Planck brane. We also explore these features in the dual scalar-tensor model by appropriate transformations. The localization property turns out to be identical in the two models. This rules out the possibility of any signature of massive KK fermions in TeV scale collider experiments due to higher curvature gravity effects.

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Inflation in the five-dimensional universe with an orbifold extra dimension

Cited by 211 publications

References 12 publications

Cosmological challenges in theories with extra dimensions and remarks on the horizon problem

Cosmological challenges in theories with extra dimensions and remarks on the horizon problem

Radion stabilization in higher curvature warped spacetime

Fermion localization in higher curvature and scalar–tensor theories of gravity

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