Article

Inflation and late time acceleration in braneworld cosmological models with varying brane tension

European Physical Journal C (Impact Factor: 5.25). 05/2010; 68(1). DOI: 10.1140/epjc/s10052-010-1348-9
Source: arXiv

ABSTRACT Braneworld models with variable brane tension $\lambda $ introduce a new
degree of freedom that allows for evolving gravitational and cosmological
constants, the latter being a natural candidate for dark energy. We consider a
thermodynamic interpretation of the varying brane tension models, by showing
that the field equations with variable $\lambda $ can be interpreted as
describing matter creation in a cosmological framework. The particle creation
rate is determined by the variation rate of the brane tension, as well as by
the brane-bulk energy-matter transfer rate. We investigate the effect of a
variable brane tension on the cosmological evolution of the Universe, in the
framework of a particular model in which the brane tension is an exponentially
dependent function of the scale factor. The resulting cosmology shows the
presence of an initial inflationary expansion, followed by a decelerating
phase, and by a smooth transition towards a late accelerated de Sitter type
expansion. The varying brane tension is also responsible for the generation of
the matter in the Universe (reheating period). The physical constraints on the
model parameters, resulted from the observational cosmological data, are also
investigated.

0 Bookmarks
 · 
79 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Braneworld models with variable tension are investigated, and the corrections on the black string horizon along the extra dimension are provided. Such corrections are encrypted in additional terms involving the covariant derivatives of the variable tension on the brane, providing profound consequences concerning the black string horizon variation along the extra dimension, near the brane. The black string horizon behavior is shown to be drastically modified by the terms corrected by the brane variable tension. In particular, a model motivated by the phenomenological interesting case regarding Eotvos branes is investigated. It forthwith provides further physical features regarding variable tension braneworld scenarios, heretofore concealed in all previous analysis in the literature. All precedent analysis considered uniquely the expansion of the metric up to the second order along the extra dimension, what is able to evince solely the brane variable tension absolute value. Notwithstanding, the expansion terms aftermath, further accomplished in this paper from the third order on, elicits the successive covariant derivatives of the brane variable tension, and their respective coupling with the extrinsic curvature, the Weyl tensor, and the Riemann and Ricci tensors, as well as the scalar curvature. Such additional terms are shown to provide sudden modifications in the black string horizon in a variable tension braneworld scenario
    Physical Review D 02/2012; 85(4). · 4.69 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Brane and warped Dvali-Gabadadze-Porrati inflationary universe models in the context of intermediate inflation are studied. In both models we consider that the energy density is a standard scalar field and we discuss the evolution of the universe during the slow-roll inflation. Also, we describe the conditions for these models. The corresponding Wilkinson Microwave Anisotropy Probe seven year data are utilized to fix some parameters in our models. Our results are compared to those found in General Relativity.
    European Physical Journal C 09/2013; 73(6). · 5.25 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Regular black strings solutions associated to a dynamical Friedmann-Robertson-Walker braneworld are obtained as a particular case of a bulk metric in the context of a variable tension braneworld. By analyzing the 5D Kretschmann invariants, we show that the variable brane tension is capable of attenuating the bulk physical singularities along some eras of the evolution of the Universe. nIn particular, the black string is analyzed for the McVittie metric on an Eötvös fluid braneworld, wherein the fluid dynamical brane tension depends on the brane temperature. The whole bulk is shown to be regular for a universe dominated by nonrelativistic matter or by relativistic matter/radiation, as the cosmological time elapses. In a particular case, the black strings are shown to have finite extension along the extra dimension, which prominently modify the higher-dimensional soft physical singularities. For a universe dominated by matter or radiation, we show that the bulk is regular as the cosmological time elapses, as an effect of the variable brane tension.
    Physical Review D 08/2014; 90:047902. · 4.69 Impact Factor

Full-text (2 Sources)

View
9 Downloads
Available from
May 16, 2014