Abstract:
Slow-roll inflation is analyzed in the context of modified gravity within the Palatini
formalism. As shown in the literature, inflation in this framework requires the presence of non-traceless
matter; otherwise, it does not occur just as a consequence of the nonlinear gravitational terms of the
action. Nevertheless, by including a single scalar field that plays the role of the inflaton, slow-roll
inflation can be performed in these theories, where the equations lead to an effective potential that
modifies the dynamics. We obtain the general slow-roll parameters and analyze a simple model to
illustrate the differences introduced by the gravitational terms under the Palatini approach, and the
modifications on the spectral index and the tensor to scalar ratio predicted by the model.
