Preheating in Palatini Higgs inflation on the lattice

Understand

We study preheating following Higgs inflation in the Palatini formulation of gravity.

• We numerically evolve perturbations of the radial mode of the Higgs field and that of three scalars modeling the gauge bosons.
• We compare the two non-perturbative mechanisms of growth of excitations -- parametric resonance and tachyonic instability -- and confirm that the latter plays the dominant role.
• Our results provide further evidence that preheating in Palatini Higgs inflation happens within a single oscillation of the Higgs field about the bottom of its potential, consistent with the approximation of an instantaneous preheating.