Natural inflation in Palatini $F(R)$

Abstract

$F(R)$ Palatini gravity provides a robust framework for constructing viable inflationary potentials. In this study, we examine natural inflation and show that its consistency with observational data can be restored when the model is embedded within $F(R)$ Palatini gravity, specifically for $F(R)=R+\alpha R^n$ with $7/4\lesssim n\le 2$. For completeness, we also demonstrate that models with $n>2$ do not yield comparable improvements, achieving partial agreement with the data only in the limit $n\to 2$.

arXiv comment13 pages, 6 figures, refs. added, matches the published version, acknowledgments updated

References in corpus (34)

• The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: cosmological analysis of the DR12 galaxy sample
• Planck 2018 results. X. Constraints on inflation
• The 2dF Galaxy Redshift Survey: Spectra and redshifts
• BICEP / Keck XIII: Improved Constraints on Primordial Gravitational Waves using Planck, WMAP, and BICEP/Keck Observations through the 2018 Observing Season
• Completing Natural Inflation
• Inflation with Non-Minimal Coupling: Metric vs. Palatini Formulations
• Cosmological perturbations in the Palatini formulation of modified gravity
• A review of Axion Inflation in the era of Planck
• Palatini inflation in models with an $R^2$ term
• Inflation with $R^2$ term in the Palatini formalism
• Reheating in $R^2$ Palatini inflationary models
• Rescuing Quartic and Natural Inflation in the Palatini Formalism
• Dynamically induced Planck scale and inflation in the Palatini formulation
• Natural Warm Inflation
• Fractional attractors in light of the latest ACT observations
• Equivalence of inflationary models between the metric and Palatini formulation of scalar-tensor theories
• Quasi-Conformal Models and the Early Universe
• Quintessential inflation in Palatini $f(R)$ gravity
• Palatini $R^2$ Quintessential Inflation
• Tachyonic Preheating in Palatini $R^2$ Inflation
• Implications of Palatini gravity for inflation and beyond
• Natural Inflation with a periodic non-minimal coupling
• On the viability of m**2 phi**2 and natural inflation
• BICEP/Keck data and Quadratic Gravity
• Natural-Scalaron Inflation
• Natural Metric-Affine Inflation
• Non-minimally coupled Natural Inflation: Palatini and Metric formalism with the recent BICEP/Keck
• Observable Primordial Gravitational Waves from Non-minimally Coupled $R^2$ Palatini Modified Gravity
• Scalar-tensor extension of Natural Inflation
• Palatini $F(R,X)$: a new framework for inflationary attractors
• Beyond (and back to) Palatini quadratic gravity and inflation
• Natural Inflation with Exponentially Small Tensor-To-Scalar Ratio
• (Multi-field) Natural Inflation and Gravitational Waves
• Natural inflation in Palatini $F(R,X)$