- Letter
Ward identity constraints on loop corrections in non-attractor inflation
Phys. Rev. D 114, L021306 – Published 28 July, 2026
DOI: https://doi.org/10.1103/23jj-5cfm
Abstract
The conservation of superhorizon curvature perturbations in strongly interacting inflationary models, particularly in the presence of quantum-loop corrections, remains a topic of active debate. We found that this conservation is essentially a direct consequence of the background-fluctuation splitting symmetry. We demonstrate that the associated Ward identity imposes strict nonperturbative constraints on the infrared power spectrum. This finding provides a rigorous, symmetry-based framework for understanding nonlinear quantum fluctuations in the primordial universe.
