{"about":{"site":"https://codewithpapers.app","non_affiliation":"Code with Papers and Syntology are not affiliated with, endorsed by, or sponsored by Papers with Code, Meta, or the pwc-archive mirror.","licence":"CC BY-SA 4.0","licence_url":"https://creativecommons.org/licenses/by-sa/4.0/legalcode","attribution":"https://codewithpapers.app/attribution","modified":"archive material modified by Syntology; see the attribution page"},"url":"/paper/towards-hybrid-inflation-with-n-s-1-in-light","title":"Towards hybrid inflation with $n_s=1$ in light of Hubble tension and primordial gravitational waves","arxiv_id":"2205.02478","date":"2022-05-05","proceeding":null,"authors":["Gen Ye","Jun-Qian Jiang","Yun-Song Piao"],"abstract":"Recently, it has been found that complete resolution of the Hubble tension might point to a scale-invariant Harrison-Zeldovich spectrum of primordial scalar perturbation, i.e. $n_s=1$ for $H_0\\sim 73$km/s/Mpc. We show that for well-known slow-roll models, if inflation ends by a waterfall instability with respect to another field in the field space while inflaton is still at a deep slow-roll region, $n_s$ can be lifted to $n_s= 1$. A surprise of our result is that with pre-recombination early dark energy, chaotic $\\phi^2$ inflation, ruled out by Planck+BICEP/Keck in standard $\\Lambda$CDM, can be revived, which is now well within testable region of upcoming cosmic microwave background B-mode experiments.","url_abs":"https://arxiv.org/abs/2205.02478v2","url_pdf":"https://arxiv.org/pdf/2205.02478v2.pdf","source":{"archive":"pwc-archive (Hugging Face), CC BY-SA 4.0","snapshot":"2025-07-28","licence_url":"https://creativecommons.org/licenses/by-sa/4.0/legalcode","row_kind":"links_only","authors_date_abstract":"arXiv metadata, CC0 1.0 (https://info.arxiv.org/help/license), from the Kaggle arXiv metadata snapshot of 2026-09-12"},"code_links":[{"paper_slug":"towards-hybrid-inflation-with-n-s-1-in-light","repo_url":"https://github.com/genye00/class_multiscf","is_official":1,"mentioned_in_paper":1,"mentioned_in_github":0,"framework":"none","reach":null}],"tasks":[],"methods":[],"datasets_introduced":[],"methods_introduced":[],"results":[],"syntology":{"atlas_url":null,"mcp":null,"developers":"https://syntology.ai/developers"},"arxiv_metadata":null,"syntology_extracted_results":null}