Numerical study of some generalizations of the Starobinsky inflationary model

In this work, a numerical study of three Starobinsky-type inflationary scenarios has been performed: the α α -Starobinsky inflationary model, the power-law Starobinsky inflationary model, and the power-law α α -Starobinsky inflationary model. For an appropriate choice of parameters, each scenario reproduces the standard Starobinsky limit. For each case, we derive the relevant slow-roll expressions in order to compute numerically the scalar and tensor power spectra over the parameter space in each case and evaluate the associated inflationary observables. Finally, we provide a comparative analysis in the (nS,AS) ( n S , A S ) and (r,nS) ( r , n S ) parameter spaces, presented via contour plots. Our results indicate that, for certain choices of parameters, all the α α -Starobinsky model, the power-law α α -Starobinsky model, and the power-law alpha -Starobinsky models are favored by Planck 2018 observations.