English

Very Hairy Inflation

High Energy Physics - Theory 2022-05-31 v2 Cosmology and Nongalactic Astrophysics General Relativity and Quantum Cosmology High Energy Physics - Phenomenology

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 Vϕp+V \sim \phi^p + \ldots with p1/2p \lesssim 1/2, limited to N2540 N \lesssim 25 - 40 efolds in the first stage of inflation, continue to fit the CMB. They yield 0.96ns0.970.96 \lesssim n_s \lesssim 0.97, and produce relic gravity waves with 0.006r0.0350.006 \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 fNLeqO(1)O(10)f_{NL}^{eq} \simeq {\cal O}(1) - {\cal O}(10), close to the current observational bounds. Finally, in multi-stage rollercoaster, an inflaton-hidden sector U(1)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 H0H_0 tension using early dark energy generically raise nsn_s. This may significantly alter the impact of BICEP/{\it Keck} data on models of inflation.

Keywords

Cite

@article{arxiv.2112.13861,
  title  = {Very Hairy Inflation},
  author = {Guido D'Amico and Nemanja Kaloper and Alexander Westphal},
  journal= {arXiv preprint arXiv:2112.13861},
  year   = {2022}
}

Comments

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

R2 v1 2026-06-24T08:33:00.954Z