Evolution of spherical over-densities in tachyon scalar field model

Abstract

We study the tachyon scalar field model in flat FRW cosmology with the particular potential $ϕ^{-2}$ and the scale factor behavior $a(t)=t^n$. We consider the spherical collapse model and investigate the effects of the tachyon scalar field on the structure formation in flat FRW universe. We calculate $δ_{c}(z_{c})$, $λ(z_{c})$, $ξ(z_{c})$, $Δ_{V}(z_{c})$, $\log [νf(ν)]$ and $\log [n(k)]$ for the tachyon scalar field model and compare the results with the results of EdS model and $ΛCDM$ model. It is shown that in the tachyon scalar field model the structure formation may occur earlier, in comparison to the other models.

14 pages, 15 figures, revision