Abstract

Recent measurements from the Atacama Cosmology Telescope (ACT), combined with Planck and DESI data, suggest a scalar spectral index ns higher than the Planck 2018 baseline, thereby placing conventional attractor-type inflationary models such as Starobinsky R2 and Higgs inflation under increasing tension at the ≳2σ level. In this work, we examine quantum-corrected ϕ4 inflation with a non-minimal coupling to gravity. Introducing an anomalous scaling parameter γ to capture quantum corrections to the effective potential, we derive analytic expressions for the inflationary observables ns and r. Confronting these predictions with ACT, Planck, and BAO+lensing constraints, we demonstrate that modest values of γ can raise ns into the ACT-preferred range while maintaining a strongly suppressed tensor-to-scalar ratio. For instance, with N=60 and γ≃0.006, the model predicts ns≃0.974 and r≃0.007, in excellent agreement with current bounds. We further investigate preheating dynamics, focusing on particle production via parametric resonance in quantum-corrected ϕ4 inflation with a non-minimal coupling to gravity. In this scenario, the inflaton ϕ couples to an additional scalar χ through an interaction g2ϕ2χ2. In Minkowski spacetime, the resonance dynamics reduce to the Mathieu equation, and we find that broad resonance can be readily achieved, leading to efficient particle production.