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arXiv · 2502.08707

Conservation of superhorizon curvature perturbations at one loop: Backreaction in the in-in formalism and Renormalization

Keisuke Inomata
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Abstract

We show that the superhorizon-limit curvature perturbations are conserved at one-loop level in single-field inflation models with a transient non-slow-roll period. We take the spatially-flat gauge, where the backreaction plays a crucial role for the conservation of superhorizon curvature perturbations unless the counter terms are tuned. We calculate the backreaction with the in-in formalism. In addition, we explicitly show the renormalization of the UV divergences with the counter terms.

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Keisuke Inomata. 2025-02-12. Conservation of superhorizon curvature perturbations at one loop: Backreaction in the in-in formalism and Renormalization. https://doi.org/10.1103/physrevd.111.103504

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