29 research outputs found
Applications of scalar attractor solutions to Cosmology
We develop a framework to study the phase space of a system consisting of a
scalar field rolling down an arbitrary potential with varying slope and a
background fluid, in a cosmological setting. We give analytical approximate
solutions of the field evolution and discuss applications of its features to
the issues of quintessence, moduli stabilisation and quintessential inflation.Comment: 9 pages, 7 figures. Accepted for publication in PR
Asymptotic behavior of w in general quintom model
For the quintom models with arbitrary potential , the
asymptotic value of equation of state parameter w is obtained by a new method.
In this method, w of stable attractors are calculated by using the ratio (d ln
V)/(d ln a) in asymptotic region. All the known results, have been obtained by
other methods, are reproduced by this method as specific examples.Comment: 8 pages, one example is added, accepted for publication in Gen. Rel.
Gra
Renormalization Group Approach to Generalized Cosmological models
We revisit here the problem of generalized cosmology using renormalization
group approach. A complete analysis of these cosmologies, where specific models
appear as asymptotic fixed-points, is given here along with their linearized
stability analysis.Comment: 10 pages, to appear in the International Journal of Theoretical
Physic
Cosmological evolution of general scalar fields in a brane-world cosmology
We study the cosmology of a general scalar field and barotropic fluid during
the early stage of a brane-world where the Friedmann constraint is dominated by
the square of the energy density. Assuming both the scalar field and fluid are
confined to the brane, we find a range of behaviour depending on the form of
the potential. Generalising an approach developed for a standard Friedmann
cosmology, in \cite{delaMacorra:1999ff}, we show that the potential dependence
can be described through a parameter , where is the 5-dimensional Planck mass, is
the Hubble parameter and . For the case where
asymptotes to zero, we show that the solution exhibits stable
inflationary behaviour. On the other hand if it approaches a finite constant,
then . For
asymptotically, we find examples where it does so both with and without
oscillating. In the latter case, the barotropic fluid dominates the scalar
filed asymptotically. Finally we point out an interesting duality which leads
to identical evolution equations in the high energy dominated regime
and the low energy dominated regime.Comment: 10 pages, 3 figure