Fixing the renormalization of inflationary loops via Ward identities

A bstract Evaluating quantum loop corrections to curvature perturbations in non-attractor inflation presents theoretical ambiguities. A crucial aspect of this challenge arises from unconstrained finite contributions to renormalization counterterms and from regularization-scheme dependence. In this work, we derive Ward identities via the path integral formalism based on the large gauge symmetry of the background-perturbation split. These identities are shown to impose nontrivial, model-independent constraints on the renormalization procedure. Provided the ultraviolet completion respects this symmetry, the Ward identities constrain the infrared evolution of the power spectrum and fix the residual finite ambiguity. This symmetry-based framework offers a systematic criterion for addressing recent theoretical discrepancies concerning one-loop corrections in ultra-slow-roll inflation.