A Minimal Sub-Planckian Axion Inflation Model with Large Tensor-to-Scalar Ratio

Abstract

We present a minimal axion inflation model which can generate a large tensor-to-scalar ratio while remaining sub-Planckian. The modulus of a complex scalar field $\Phi$ with a $\lambda |\Phi {|}^4$ potential couples directly to the gauge field of a strongly-coupled sector via a term of the form $(|\Phi |/M_{Pl}{)}^{m}F\tilde{F}$. This generates a minimum of the potential which is aperiodic in the phase. The resulting inflation model is equivalent to a ${\varphi }^{4/(m+1)}$ chaotic inflation model. For the natural case of a leading-order portal-like interaction ${\Phi }^{†}\Phi F\tilde{F}$, the model is equivalent to a ${\varphi }^{4/3}$ chaotic inflation model and predicts a tensor-to-scalar ratio $r=16/3N=0.097$ and a scalar spectral index $n_s=1-5/3N=0.970$. The value of $|\Phi |$ remains sub-Planckian throughout the observable era of inflation, with $|\Phi |\lesssim 0.01M_{Pl}$ for $N\lesssim 60$ when $\lambda \sim 1$.

arXiv commentOne minor alteration. Version to be published in JCAP

References in corpus (17)

• BICEP2 I: Detection Of B-mode Polarization at Degree Angular Scales
• Planck 2013 results. XXII. Constraints on inflation
• Monodromy in the CMB: Gravity Waves and String Inflation
• Gravity Waves and Linear Inflation from Axion Monodromy
• What would we learn by detecting a gravitational wave signal in the cosmic microwave background anisotropy?
• Completing Natural Inflation
• N-flation
• Natural Chaotic Inflation in Supergravity
• A Natural Framework for Chaotic Inflation
• An Ignoble Approach to Large Field Inflation
• BICEP2 II: Experiment and Three-Year Data Set
• A review of Axion Inflation in the era of Planck
• Dante's Inferno
• Aligned Natural Inflation: Monodromies of two Axions
• BICEP2 implications for single-field slow-roll inflation revisited
• Discovery of Large Scale Tensor Mode and Chaotic Inflation in Supergravity
• Sub-Planckian Two-Field Inflation Consistent with the Lyth Bound

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• Signatures of Planck Corrections in a Spiralling Axion Inflation Model
• Power spectrum oscillations from Planck-suppressed operators in effective field theory motivated monodromy inflation
• Multi-field inflation and the field-space metric
• New- vs. chaotic-inflations
• The Upper Bound on the Tensor-to-Scalar Ratio Consistent with Quantum Gravity
• Flavored axion-monodromy inflation
• The (relative) size does not matter in inflation