Non-singular Universes à la Palatin

Gonzalo J. Olmo

It has recently been shown that f(R) theories formulated in the metric-affine (or Palatini) variational formalism are able to avoid the big bang singularity yielding instead a bouncing solution. The mechanism responsible for this behaviour is similar to that observed in the effective dynamics of loop quantum cosmology and an f(R) theory exactly reproducing that dynamics has been found.
I will show that considering more general actions, with quadratic contributions of the Ricci tensor, results in a much richer phenomenology than in the f(R) case, yielding bouncing solutions even in anisotropic (Bianchi I) scenarios. I will discuss some implications of these new results.