{"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/cosmic-enu-an-emulator-for-the-non-linear","title":"Cosmic-Enu: An emulator for the non-linear neutrino power spectrum","arxiv_id":"2311.11240","date":"2023-11-19","proceeding":null,"authors":["Amol Upadhye","Juliana Kwan","Ian G. McCarthy","Jaime Salcido","Kelly R. Moran","Earl Lawrence","Yvonne Y. Y. Wong"],"abstract":"Cosmology is poised to measure the neutrino mass sum $M_\\nu$ and has identified several smaller-scale observables sensitive to neutrinos, necessitating accurate predictions of neutrino clustering over a wide range of length scales. The FlowsForTheMasses non-linear perturbation theory for the massive neutrino power spectrum, $\\Delta^2_\\nu(k)$, agrees with its companion N-body simulation at the $10\\%-15\\%$ level for $k \\leq 1~h/$Mpc. Building upon the Mira-Titan IV emulator for the cold matter, we use FlowsForTheMasses to construct an emulator for $\\Delta^2_\\nu(k)$ covering a large range of cosmological parameters and neutrino fractions $\\Omega_{\\nu,0} h^2 \\leq 0.01$, which corresponds to $M_\\nu \\leq 0.93$~eV. Consistent with FlowsForTheMasses at the $3.5\\%$ level, it returns a power spectrum in milliseconds. Ranking the neutrinos by initial momenta, we also emulate the power spectra of momentum deciles, providing information about their perturbed distribution function. Comparing a $M_\\nu=0.15$~eV model to a wide range of N-body simulation methods, we find agreement to $3\\%$ for $k \\leq 3 k_\\mathrm{FS} = 0.17~h/$Mpc and to $19\\%$ for $k \\leq 0.4~h/$Mpc. We find that the enhancement factor, the ratio of $\\Delta^2_\\nu(k)$ to its linear-response equivalent, is most strongly correlated with $\\Omega_{\\nu,0} h^2$, and also with the clustering amplitude $\\sigma_8$. Furthermore, non-linearities enhance the free-streaming-limit scaling $\\partial \\log(\\Delta^2_\\nu / \\Delta^2_{\\rm m}) / \\partial \\log(M_\\nu)$ beyond its linear value of 4, increasing the $M_\\nu$-sensitivity of the small-scale neutrino density.","url_abs":"https://arxiv.org/abs/2311.11240v1","url_pdf":"https://arxiv.org/pdf/2311.11240v1.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":"cosmic-enu-an-emulator-for-the-non-linear","repo_url":"https://github.com/upadhye/cosmic-enu","is_official":1,"mentioned_in_paper":1,"mentioned_in_github":1,"framework":"none","reach":null}],"tasks":[],"methods":[],"datasets_introduced":[],"methods_introduced":[],"results":[],"syntology":{"syntology_url":null,"atlas_url":null,"mcp":null,"developers":"https://syntology.ai/developers"},"arxiv_metadata":null,"syntology_extracted_results":null}