Role of the counterterms in the conservation of superhorizon curvature perturbations at one loop

Abstract: Recently, several papers have claimed that superhorizon curvature perturbations are not conserved at the one-loop level in single-field inflation models if there is a transient ultra-slow-roll period. In this work, we point out that the contributions from the counterterms were overlooked in the papers. We show that the counterterm contributions play a crucial role in canceling the one-loop power spectrum of superhorizon curvature perturbations in the comoving gauge.