Pole inflation from extended metric-affine gravity

We study inflation in the framework of extended metric-affine F® gravity, where all even-parity quadratic invariants of torsion and non-metricity are included in the Lagrangian alongside the F® term. The extended theory admits a scalar-tensor description with a non-canonical kinetic term featuring poles. As a result, the inflationary dynamics and predictions for observables of this model are insensitive to the specific form of F®, since they are dominated by the structure of the poles (order and residue). We analyze both a simplified version analytically and the full eleven-parameter theory, and we classify the models based on whether they feature second-order poles, whether they are free from ghosts, and whether they predict a sufficiently small tensor-to-scalar ratio. By relaxing the ghost-free requirement to only exclude ghosts near the pole (where inflation occurs), we demonstrate that we can significantly enlarge the set of viable models. We thus show that extended metric-affine F® gravity can act as a robust framework for inflation, reproducing the attractor predictions for the spectral index and tensor-to-scalar ratio.