Abstract
In this paper, we have studied the general evolution of spherical over-densities for thawing class of scalar field dark energy (DE) models. We have considered the scalar fields having canonical as well as non-canonical kinetic energy (particularly the Born-Infeld form of kinectic term) with various type of potentials, and also investigated the situation where DE is homogeneous as well as the case where DE virializes together with matter (inhomogeneous). Our study has shown that models with linear potential, in particular, can have significant deviation from the ΛCDM model in terms of density contrast at the time of virialization, and further study of the cluster number counts has shown that the total cluster number counts of different DE models can have substantial deviation from ΛCDM, and this deviation is most significant for all the models we have considered.
Highlights
One of the most significant discoveries in cosmology in recent years is the fact that our universe is currently going through an accelerated expansion phase(Riess 2004; Knop 2003)
In a recent paper by Sen et al (Sen 2010), assumption of slow roll has been relaxed, but it was assumed that the scalar field is of thawing type i.e it is initially frozen at w = −1 due to large Hubble damping
Knowing that models with linear potential as well as models with Pseudo-Nambu Goldstone Boson (PNGB) type potential deviate more from ΛCDM model in comparison to other potentials, we study the size of the collapsed objects for these potentials for homongeneous as well as for inhomogeneous cases
Summary
One of the most significant discoveries in cosmology in recent years is the fact that our universe is currently going through an accelerated expansion phase(Riess 2004; Knop 2003). As radiation/matter rapidly dilutes due to the expansion of the universe and the background energy density becomes comparable to scalar field energy density, the field breaks away from its frozen state and evolves slowly to the region with w > −1 In this case, the model needs some degree of fine tuning of the initial conditions in order to achieve a viable late time evolution. In a recent paper by Sen et al (Sen 2010), assumption of slow roll has been relaxed, but it was assumed that the scalar field is of thawing type i.e it is initially frozen at w = −1 due to large Hubble damping With these choices the evolution of a variety of scalar field models having both canonical and non-canonical kinetic terms have been studied.
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