Higgs-Dilaton Inflation in Einstein-Cartan gravity
  We study the phenomenology of the Higgs-Dilaton model in the context of
Einstein-Cartan gravity, focusing on the separate impact of the Holst and
Nieh-Yan terms on the inflationary observables. Using analytical and numerical
techniques, we show the predictions of these scenarios to display an
attractor-like behaviour intrinsically related to the curvature of the
field-space manifold in the metric formulation of the theory. Beyond that, the
analysis of the Nieh-Yan case reveals the existence of an additional attractor
solution induced by a cubic pole in the inflaton kinetic term that becomes
relevant at large dilaton couplings. This constitutes a unique feature of the
Einstein-Cartan formulation as compared to the metric and Palatini
counterparts.
