Preheating in radiative corrections to $\phi^4$ inflation with
  non-minimal coupling in Palatini formulation
  We discuss the impact of the preheating stage in radiative corrections due to
interaction of the inflaton to fermions to $\phi^4$ inflation with non-minimal
coupling in Palatini formulation. In Palatini inflation with large non-minimal
coupling the field is allow to return to the plateau region during the
reheating stage, so the average equation of state per oscillations is closer to
$-1$ than to $1/3$. The incursion in the plateau leads, however, to a highly
efficient tachyonic instability able to reheat the Universe in less than one
e-fold. By taking into account prescription II discussed in the literature, in
the wide range of $\kappa-\xi$, we figure out spectral index $n_s$ and
tensor-to-scalar ratio $r$ which are compatible with the data given by the Keck
Array/BICEP2 and Planck collaborations.
