1202.4154 (M. Malekjani et al.)

Statefinder diagnosis and the interacting ghost model of dark energy    [PDF]

M. Malekjani, A. Khodam-Mohammadi

A new model of dark energy namely "ghost dark energy model" has recently been
suggested to interpret the positive acceleration of cosmic expansion. The
energy density of ghost dark energy is proportional to the hubble parameter. In
this paper we perform the statefinder diagnostic tool for this model both in
flat and non-flat universe. We discuss the dependency of the evolutionary
trajectories in $s-r$ and $q-r$ planes on the interaction parameter between
dark matter and dark energy as well as the spatial curvature parameter of the
universe. Eventually, in the light of SNe+BAO+OHD+CMB observational data, we
plot the evolutionary trajectories in $s-r$ and $q-r$ planes for the best fit
values of the cosmological parameters and compare the interacting ghost model
with other dynamical dark energy models. We show that the evolutionary
trajectory of ghost dark energy in statefinder diagram is similar to
holographic dark energy model. It has been shown that the statefinder location
of $\Lambda$CDM is in good agreement with observation and therefore the dark
energy models whose current statefinder values are far from the $\Lambda$CDM
point can be ruled out.

View original: http://arxiv.org/abs/1202.4154