3 research outputs found
Cosmological observations in scalar-tensor quintessence
The framework for considering the astronomical and cosmological observations
in the context of scalar-tensor quintessence in which the quintessence field
also accounts for a time dependence of the gravitational constant is developed.
The constraints arising from nucleosynthesis, the variation of the constant,
and the post-Newtonian measurements are taken into account. A simple model of
supernovae is presented in order to extract the dependence of their light
curves with the gravitational constant; this implies a correction when fitting
the luminosity distance. The properties of perturbations as well as CMB
anisotropies are also investigated.Comment: 26 pages, 22 figures, to appear in PR
Statefinder Diagnostic for Dilaton Dark Energy
Statefinder diagnostic is a useful method which can differ one dark energy
model from the others. The Statefinder pair is algebraically related
to the equation of state of dark energy and its first time derivative. We apply
in this paper this method to the dilaton dark energy model based on Weyl-Scaled
induced gravitational theory. We investigate the effect of the coupling between
matter and dilaton when the potential of dilaton field is taken as the Mexican
hat form. We find that the evolving trajectory of our model in the
diagram is quite different from those of other dark energy models.Comment: 6 pages, 4 figures, type errors corrected, reference no. changed,
accepted by Astrophysics and Space Scienc