Exact Renormalisation Group Evolution of the Inflation Dynamics: Reconciling $\alpha$-Attractors with ACT

TL;DR

This paper develops a non-perturbative renormalisation group framework for inflation, revealing quantum corrections that modify inflationary trajectories and align $oldsymbol{ extalpha}$-attractor models with recent ACT observations.

Contribution

It introduces a novel RG approach to inflation dynamics, incorporating quantum effects and explaining the compatibility of $ extalpha$-attractors with observational data.

Findings

RG flow causes dynamical destabilisation of inflationary trajectories

Quantum corrections can reconcile $ extalpha$-attractors with ACT data

Inflation terminates prematurely due to RG effects

Abstract

We present a non-perturbative framework for the dynamics of slow-roll inflation that consistently incorporates quantum corrections, based on an alternative functional renormalisation group (RG) approach. We derive the coupled Friedmann-RG flow equations governing the joint evolution of spacetime, the inflaton field, and its effective potential. Applying this formalism to $\alpha$-attractor E-models, we find that the RG flow induces a dynamical destabilisation of the inflationary trajectory, leading to a premature termination of slow roll. Remarkably, the resulting predictions bring $\alpha$-attractors into full agreement with the latest ACT data without introducing new physics beyond a consistent quantum-corrected treatment of the inflaton dynamics.