Luisa Jaime (Institute for Theoretical Physics, Heidelberg University, Germany)
We introduce a different approach in f(R) gravity. Our approach avoids the mapping to scalar tensor theories using the Ricci scalar itself as an 'extra' degree of freedom. In this talk we will present this formalism and we will analyze the equation of state (EOS) of the geometric dark energy related with the extra terms in f(R), including the comparison of several EOS that have been proposed in the past. Finally we will show how some models could be in a good agreement with the value of H measured by using Barionic Acoustic Oscillations.