1207.5472 (D. Saez-Gomez)

Cosmological evolution, future singularities and Little Rip in viable
f(R) theories and their scalar-tensor counterpart    [PDF]

D. Saez-Gomez

Modified f(R) gravity is one of the most promising candidates for dark energy, and even for the unification of the whole cosmological evolution, including the inflationary phase. Inside this class of theories, the so-called viable modified gravities represent realistic theories that are capable to reproduce late-time acceleration, and satisfy strong constraints at local scales, where General Relativity is recovered. In the present work, the cosmological evolution for some of these models is analyzed, which indicates that these f(R) theories may lead to a phantom phase in the universe evolution. Furthermore, the scalar-tensor equivalence of f(R) gravity is also considered, which can provide important properties on this kind of models. Moreover, the possibility of the occurrence of future singularities as well as the so-called Little Rip are studied.

View original: http://arxiv.org/abs/1207.5472