{"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/on-the-road-to-percent-accuracy-v-the-non","title":"On the road to percent accuracy V: the non-linear power spectrum beyond $Λ$CDM with massive neutrinos and baryonic feedback","arxiv_id":"2105.12114","date":"2021-05-25","proceeding":null,"authors":["Benjamin Bose","Bill S. Wright","Matteo Cataneo","Alkistis Pourtsidou","Carlo Giocoli","Lucas Lombriser","Ian G. McCarthy","Marco Baldi","Simon Pfeifer","Qianli Xia"],"abstract":"In the context of forthcoming galaxy surveys, to ensure unbiased constraints on cosmology and gravity when using non-linear structure information, percent-level accuracy is required when modelling the power spectrum. This calls for frameworks that can accurately capture the relevant physical effects, while allowing for deviations from $\\Lambda$CDM. Massive neutrino and baryonic physics are two of the most relevant such effects. We present an integration of the halo model reaction frameworks for massive neutrinos and beyond-$\\Lambda$CDM cosmologies. The integrated halo model reaction, combined with a pseudo power spectrum modelled by HMCode2020 is then compared against $N$-body simulations that include both massive neutrinos and an $f(R)$ modification to gravity. We find that the framework is 4% accurate down to at least $k\\approx 3 \\, h/{\\rm Mpc}$ for a modification to gravity of $|f_{\\rm R0}|\\leq 10^{-5}$ and for the total neutrino mass $M_\\nu \\equiv \\sum m_\\nu \\leq 0.15$ eV. We also find that the framework is 4% consistent with EuclidEmulator2 as well as the Bacco emulator for \\B{most of the considered} $\\nu w$CDM cosmologies down to at least $k \\approx 3 \\, h$/Mpc. Finally, we compare against hydrodynamical simulations employing HMCode2020's baryonic feedback modelling on top of the halo model reaction. For $\\nu \\Lambda$CDM cosmologies we find 2% accuracy for $M_\\nu \\leq 0.48$eV down to at least $k\\approx 5h$/Mpc. Similar accuracy is found when comparing to $\\nu w$CDM hydrodynamical simulations with $M_\\nu = 0.06$eV. This offers the first non-linear, theoretically general means of accurately including massive neutrinos for beyond-$\\Lambda$CDM cosmologies, and further suggests that baryonic, massive neutrino and dark energy physics can be reliably modelled independently.","url_abs":"https://arxiv.org/abs/2105.12114v2","url_pdf":"https://arxiv.org/pdf/2105.12114v2.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":"on-the-road-to-percent-accuracy-v-the-non","repo_url":"https://github.com/nebblu/ReACT","is_official":1,"mentioned_in_paper":1,"mentioned_in_github":0,"framework":"none","reach":null},{"paper_slug":"on-the-road-to-percent-accuracy-v-the-non","repo_url":"https://github.com/nebblu/actio-reactio","is_official":0,"mentioned_in_paper":0,"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}