Higgs-Palatini Inflation and Unitarity
  In the Higgs inflation scenario the Higgs field is strongly coupled to the
Ricci scalar in order to drive primordial inflation. However, in its original
form in pure metric formulation of gravity, the ultraviolet (UV) cutoff of the
Higgs interactions and the Hubble rate are of the same magnitude, and this
makes the whole inflationary evolution dependent of the unknown UV completion
of the Higgs sector. This problem, the unitarity violation, plagues the Higgs
inflation scenario. In this letter we show that, in the Palatini formulation of
gravitation, Higgs inflation does not suffer from unitarity violation since the
UV cutoff lies parametrically much higher than the Hubble rate so that unknown
UV physics does not disrupt the inflationary dynamics. Higgs-Palatini
inflation, as we call it, is, therefore, UV-safe, minimal and endowed with
predictive power.
