Very Hairy Inflation

Abstract

We revisit the rollercoaster cosmology based on multiple stages of monodromy inflation. Working within the framework of effective flux monodromy field theory, we include the full range of strong coupling corrections to the inflaton sector. We find that flattened potentials $V\sim {\varphi }^p+\dots$ with $p\lesssim 1/2$, limited to $N\lesssim 25-40$ efolds in the first stage of inflation, continue to fit the CMB. They yield $0.96\lesssim n_s\lesssim 0.97$, and produce relic gravity waves with $0.006\lesssim r\lesssim 0.035$, in full agreement with the most recent bounds from BICEP/{\it Keck}. The nonlinear derivative corrections generated by strong dynamics in EFT also lead to equilateral non-Gaussianity $f_{NL}^{eq}\simeq \mathcal{O}(1)-\mathcal{O}(10)$, close to the current observational bounds. Finally, in multi-stage rollercoaster, an inflaton-hidden sector $U(1)$ coupling can produce a tachyonic chiral vector background, which converts rapidly into tensors during the short interruption by matter domination. The produced stochastic gravity waves are chiral, and so they may be clearly identifiable by gravity wave instruments like LISA, Big Bang Observatory, Einstein Telescope, NANOgrav or SKA, depending on the precise model realization. We also point out that the current attempts to resolve the $H_0$ tension using early dark energy generically raise $n_s$. This may significantly alter the impact of BICEP/{\it Keck} data on models of inflation.

25+1 pages LaTeX, 8 figures. v2: Minor changes, references added, published in PRD

References in corpus (17)

• The Effective Field Theory of Inflation
• Observational Signatures and Non-Gaussianities of General Single Field Inflation
• BICEP / Keck XIII: Improved Constraints on Primordial Gravitational Waves using Planck, WMAP, and BICEP/Keck Observations through the 2018 Observing Season
• Monodromy in the CMB: Gravity Waves and String Inflation
• The trouble with $H_0$
• Science with the space-based interferometer LISA. IV: Probing inflation with gravitational waves
• A Natural Framework for Chaotic Inflation
• An Ignoble Approach to Large Field Inflation
• The Powers of Monodromy
• Generating PBHs and small-scale GWs in two-field models of inflation
• F-term Axion Monodromy Inflation
• D7-Brane Chaotic Inflation
• Primordial black holes and gravitational waves from resonant amplification during inflation
• Nflation: multi-field inflationary dynamics and perturbations
• Just enough inflation: power spectrum modifications at large scales
• Natural Chaotic Inflation and UV Sensitivity
• Pure Natural Inflation