Astronomy and Astrophysics – Astrophysics – Cosmology and Extragalactic Astrophysics
Scientific paper
2010-10-19
Prog. Theor. Phys. 125 (2011), 603-615
Astronomy and Astrophysics
Astrophysics
Cosmology and Extragalactic Astrophysics
Accepted for publication in Progress of Theoretical Physics, references added and typos corrected, 13 pages
Scientific paper
10.1143/PTP.125.603
We derive the equation of matter density perturbations on sub-horizon scales around a flat Friedmann-Lema\^\i tre-Robertson-Walker background for the general Lagrangian density $f(R,\GB)$ that is a function of a Ricci scalar $R$ and a Gauss-Bonnet term $\GB$. We find that the effective gravitational constant generically scales as distance squared at small distances. The effect of this diminishing of the gravitational constant might be important in the gravitational dynamics of cosmic objects such as galaxies, which can be in principle tested by observations. We also provide the general expressions for the effective anisotropic stress, which is useful to constrain modified gravity models from observations of large-scale structure and weak lensing. We also find that there is a special class of theories which evade this unusual behaviour and that the condition to belong to this special class is exactly the same as the one for not having super-luminal modes with propagation speed proportional to their wavenumber.
de Felice Antonio
Suyama Teruaki
No associations
LandOfFree
Linear growth of matter density perturbations in f(R,G) theories does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Linear growth of matter density perturbations in f(R,G) theories, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Linear growth of matter density perturbations in f(R,G) theories will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-268900