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Note on the cosmological dynamics in finite-range gravity
(2011-07-05) Sami, M.
In this note we consider the homogeneous and isotropic cosmology in the ﬁnite-range gravity theory recently proposed by Babak and Grishchuk. In this scenario the universe undergoes late time accelerated expansion if both the massive gravitons present in the model are tachyons. We carry out the phase space analysis of the system and show that the late-time acceleration is an attractor of the model.
Cosmological Dynamics of Phantom Field
(2011-07-05) Singh, Parampreet; Sami, M.; Dadhich, Naresh
We study the general features of the dynamics of the phantom ﬁeld in the cosmological context. In the case of inverse coshyperbolic potential, we demonstrate that the phantom ﬁeld can successfully drive the observed current accelerated expansion of the universe with the equation of state parameter wφ < −1. The de-Sitter universe turns out to be the late time attractor of the model. The main features of the dynamics are independent of the initial conditions and the parameters of the model. The model ﬁts the supernova data very well, allowing for −2.4 < wφ < −1 at 95 % conﬁdence level