The speaker investigates loop corrections to the primordial fluctuations in the single-field inflationary paradigm from spectator fields that experience a transition of their vacuum expectation values. This phase transition involves a classical evolution effectively driven by a negative mass term from the potential where field perturbations can grow on superhorizon scales. In this lecture, the speaker will show that the important corrections to the curvature perturbation, that can be generated by field perturbations, are frozen outside the horizon by the time of the growing phase. Yet the correction to tensor perturbation is naturally suppressed by the spatial derivative couplings between spectator fields and graviton. These results indicate that loop corrections residing in cosmological correlations may be more important than they were expected.
