On UV-completion of Palatini-Higgs inflation

Understand

We investigate the UV-completion of the Higgs inflation in the metric and the Palatini formalisms.

• It is known that the cutoff scales for the perturbative unitarity of these inflation models become much smaller than the Planck scale to be consistent with observations.
• Expecting that the low cutoff scale originates in the curvature of a field-space spanned by the Higgs fields, we consider embedding the curved field-space into a higher dimensional flat space and apply this procedure to the metric-Higgs and the Palatini-Higgs scenarios.
• The new field introduced in this way successfully flattens the field-space and UV-completes the Higgs inflation in the metric formalism.