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

European Physical Journal C (Impact Factor: 5.44). 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

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