Incorporating backreaction in one-loop corrections in ultraslow-roll inflation
Phys. Rev. D 112, 023547 – Published 28 July, 2025
DOI: https://doi.org/10.1103/nkrq-3d39
Abstract
We investigate the one-loop quantum correction to the primordial curvature power spectrum in the ultraslow-roll (USR) inflation scenario, incorporating the backreaction effect from curvature perturbations. In the spatially flat gauge, we expand the background inflation field up to second order and identify the one-loop-level backreaction term in the action. Utilizing a gauge transformation, we derive the comoving curvature interaction Hamiltonian in the presence of the backreaction term and calculate the one-loop correction using the in-in formalism. Our results reveal that the one-loop superhorizon corrections previously reported in the literature are canceled by the backreaction contributions. This finding underscores the importance of accounting for backreaction effects in the analysis of quantum corrections during USR inflation.
