{
  "abstract": "We compute the galaxy power spectrum at two-loop order in cosmological perturbation theory (effective field theory, EFT). We derive galaxy bias operators through the fifth order and obtain two-loop renormalization conditions for their bias coefficients. We also derive the relevant higher-derivative and stochastic contributions, and implement IR resummation using time-sliced perturbation theory. We obtain the complete dark-matter and galaxy renormalization conditions for the higher-derivative operators at the power spectrum, bispectrum, and trispectrum level. Having identified the redundant operators, we find that the two-loop galaxy power spectrum requires 21 additional bias, higher derivative and stochastic parameters per galaxy sample relative to the one-loop model. We compare our computation with the galaxy-galaxy and galaxy-matter power spectra from the PT Challenge N-body simulation at $z=0.61$ and find a per mille-level agreement up to $k=0.85~h$Mpc$^{-1}$. We show that even with conservative priors on all EFT parameters, the two-loop model produces an unbiased measurement of the mass fluctuation amplitude $σ_8$ with three times narrower error-bars than the linear theory model. The improvement over the one-loop model is $\\simeq 40\\%$. This suggests significant gains in the two-loop EFT analyses of galaxy clustering and galaxy--lensing two-point functions (``$2\\times2$ pt'') from CMB lensing maps and imaging surveys like Euclid, LSST, and Roman. In addition, our two-loop computation offers a probe of new physics scenarios that modify the shape of the matter power spectrum at wavenumbers $(0.4-0.8)~h$Mpc$^{-1}$ such as the presence of ultra-light axion dark matter sub-components with masses $m_a\\sim 10^{-24}$ eV.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2606.30713",
  "author_total": 1,
  "authors": [
    {
      "name": "Mikhail M. Ivanov"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/epr34ras3e7d4.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2606.30713",
  "fulltext_url": null,
  "id": "epr34ras3e7d4",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2606.30713",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "astro-ph.CO"
    ],
    [
      "arxiv",
      "gr-qc"
    ],
    [
      "arxiv",
      "hep-ph"
    ],
    [
      "arxiv",
      "hep-th"
    ],
    [
      "openalex",
      "3103|Cosmology and Gravitation Theories"
    ]
  ],
  "openalex": "W7166872943",
  "pdf_url": "https://arxiv.org/pdf/2606.30713",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-15",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/epr34ras3e7d4.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:21:41Z",
      "native_id": "2606.30713",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2606.30713"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.CO",
      "subfield": "cosmology"
    },
    {
      "field": "physics",
      "origin": "arxiv:gr-qc",
      "subfield": "gravitation"
    },
    {
      "field": "physics",
      "origin": "arxiv:hep-ph",
      "subfield": "high-energy"
    }
  ],
  "title": "Galaxy Power Spectrum at Two-Loop Order: Implications for Weak Lensing Surveys and New Physics",
  "title_text": "Galaxy Power Spectrum at Two-Loop Order: Implications for Weak Lensing Surveys and New Physics",
  "type": "preprint",
  "updated_at": "2026-10-30T12:21:41Z",
  "url": "https://research.draconitic.com/paper/epr34ras3e7d4",
  "venue": "arXiv",
  "versions": []
}