Inflationary Models with Gauss-Bonnet Coupling in Light of ACT Observations

Abstract

Recent analyses combining Atacama Cosmology Telescope (ACT) data with other cosmological datasets report a higher scalar spectral index $n_s$, creating tension with a wide range of inflationary models. Since a Gauss-Bonnet term with a coupling function $\xi (\varphi )=3\lambda /[4V(\varphi )]$ leaves $n_s$ nearly unchanged (up to a field rescaling) while reducing the tensor-to-scalar ratio $r$ by a factor $(1-\lambda )$, so choosing $(1-\lambda )$ sufficiently small effectively removes $r$ as a limiting observable, making it easier for inflationary models to satisfy the latest observational constraints and alleviating this tension. Applying this mechanism to chaotic inflation, E-models, T-models, and hilltop inflation, we find that broad regions of parameter space become consistent with the latest ACT-based CMB constraints. These results demonstrate that Gauss-Bonnet couplings can help bring a broad class of inflationary models into agreement with current CMB measurements.

11 pages, 5 figures

References in corpus (26)

• The Standard Model Higgs boson as the inflaton
• DESI 2024 VI: Cosmological Constraints from the Measurements of Baryon Acoustic Oscillations
• BICEP / Keck XIII: Improved Constraints on Primordial Gravitational Waves using Planck, WMAP, and BICEP/Keck Observations through the 2018 Observing Season
• DESI 2024 III: Baryon Acoustic Oscillations from Galaxies and Quasars
• Power spectra from an inflaton coupled to the Gauss-Bonnet term
• Primordial non-Gaussianities in general modified gravitational models of inflation
• Fractional attractors in light of the latest ACT observations
• Keeping the relation between the Starobinsky model and no-scale supergravity ACTive
• Higgs-Modular Inflation
• Reheating ACTs on Starobinsky and Higgs inflation
• Curvature corrections to Starobinsky inflation can explain the ACT results
• Enhancement of primordial curvature perturbations in $R^3$-corrected Starobinsky-Higgs inflation
• Nonminimal coupling and inflationary attractors
• Independent connection in ACTion during inflation
• Kinetically Modified Palatini Inflation Meets ACT Data
• Inflationary Dynamics and Swampland Criteria for Modified Gauss-Bonnet Gravity Compatible with GW170817
• Non-minimal coupling in light of ACT
• Increase of $n_s$ in regularized pole inflation & Einstein-Cartan gravity
• Improved Predictions on Higgs-Starobinsky Inflation and Reheating with ACT DR6 and Primordial Gravitational Waves
• Study of Goldstone Inflation in the domain of Einstein-Gauss-Bonnet gravity
• Chasing cosmic inflation: constraints for inflationary models and reheating insights
• Interacting Models of Dark Energy and Dark Matter in Einstein scalar Gauss Bonnet Gravity
• Inflationary Dynamics of Mutated Hilltop Inflation in Einstein-Gauss-Bonnet Gravity Under New Slow-Roll Approximations with Generalised Reheating
• Inflationary Dynamics in Einstein-Gauss-Bonnet Gravity Using New Slow-Roll Approximations considering Generalised Reheating
• General Einstein-Cartan quadratic gravity with derivative couplings
• Constraints on Einstein-dilaton Gauss-Bonnet gravity with Taiji

Cited by in corpus (7)

• Approximate reconstruction of inflationary potential with ACT observations
• Harrison-Zeldovich attractor: From Planck to ACT results
• Effect of Moduli Redefinitions on Fibre Inflation
• Mutated hilltop inflation in light of Planck/ACT observations
• Inflationary models in a minimally coupled $f(R,T)$ gravity: Constraints from $Planck$, BICEP/$Keck$, and ACT
• Beyond $f(\varphi )\mathcal{G}$: Gauss--Bonnet inflation with $\mu (\varphi ,X)$
• Constraints on non-canonical chaotic inflation from ACT DR6 and BICEP/Keck data