Natural Metric-Affine Inflation: Reloaded
This work re-examines natural inflation in metric-affine gravity by introducing non-minimal couplings between the inflaton field and the Nieh-Yan term. By adding a coupling with the Ricci scalar, researchers found that this modification allows for agreement with observational data while remaining viable even at sub-Planckian periodicity scales, suggesting moderately large couplings are necessary.