Speaker: Nicola Tamanini
The talk will be divided in two parts. In the first part modified theories of gravity with a nonminimal coupling between the space-time curvature and matter fields will be discussed. Conditions for the coupling to not introduce classical instabilities or superluminal propagation of perturbations will be derived and different models relevant for cosmological applications will be constrained. In the second part an extension of f(R) gravity where the gravitational action is taken to depend on a general function of both the metric and Palatini curvature scalars will be presented. The cosmological dynamics and ghost instabilities of this theory will be analysed and viable physical models will be identified.