f (R) gravity: scalar perturbations in the late Universe
Eingorn, M.; Novák, J.; Zhuk, A.
In this paper we study scalar perturbations of the
metric for nonlinear f (R) models.We consider the Universe
at the late stage of its evolution and deep inside the cell of
uniformity. We investigate the astrophysical approach in the
case of Minkowski spacetime background and two cases in
the cosmological approach, the large scalaron mass approximation
and the quasi-static approximation, getting explicit
expressions for scalar perturbations for both these cases. In
the most interesting quasi-static approximation, the scalar
perturbation functions depend on both the nonlinearity function
f (R) and the scale factor a. Hence, we can study the
dynamical behavior of the inhomogeneities (e.g., galaxies
and dwarf galaxies) including into consideration their gravitational
attraction and the cosmological expansion, and also
taking into account the effects of nonlinearity. Our investigation
is valid for functions f (R) which have stable de Sitter
points in future with respect to the present time, which is
typical for the most popular f (R) models.
type: | article |
journal: | European Physical Journal C |
volume: | 74 |
pages: | 3005 |
year: | 2014 |