{
  "abstract": "We develop an efficient three-dimensional numerical-relativity framework for primordial black-hole (PBH) formation from superhorizon curvature perturbations in a radiation-dominated Universe. We implement flux-conservative relativistic hydrodynamics in the adaptive-mesh-refinement code \\textsc{GRChombo} and introduce a cosmologically scaled Gamma-driver that allows the cosmic-time step to grow in proportion to the scale factor. For a representative long-term simulation, the scaled driver preserves the apparent-horizon mass evolution and constraint behavior while reducing the number of coarse-level advances by a factor of approximately $94$ relative to the standard driver. We also construct a conformal-time version of the moving-puncture gauge as an independent check. Applying the framework to a spherical Gaussian curvature profile, we find a collapse threshold $0.79578 < μ_c < 0.79580$ and a critical exponent $γ\\simeq 0.3559$, consistent with previous spherically symmetric results. We further fit the late-time PBH mass growth to the Zel'dovich--Novikov accretion law, demonstrating that the code can follow both near-critical collapse and long-term post-formation evolution in three dimensions. The framework provides a foundation for future studies of PBH formation beyond spherical symmetry.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2608.13206",
  "author_total": 4,
  "authors": [
    {
      "name": "Zhuan Ning"
    },
    {
      "name": "Rong-Gen Cai"
    },
    {
      "name": "Shao-Jiang Wang"
    },
    {
      "name": "Chul-Moon Yoo"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/eyx12v5r0ev2d.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2608.13206",
  "fulltext_url": null,
  "id": "eyx12v5r0ev2d",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2608.13206",
  "language": null,
  "licence": "LicenseRef-arXiv-nonexclusive-1.0",
  "licence_label": "arXiv licence",
  "licence_source": "article",
  "licence_url": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "astro-ph.CO"
    ],
    [
      "arxiv",
      "gr-qc"
    ],
    [
      "arxiv",
      "hep-ph"
    ],
    [
      "openalex",
      "3103|Cosmology and Gravitation Theories"
    ]
  ],
  "openalex": "W7203474722",
  "pdf_url": "https://arxiv.org/pdf/2608.13206",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-03",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/eyx12v5r0ev2d.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:31Z",
      "native_id": "2608.13206",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2608.13206"
    }
  ],
  "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": "Long-term 3+1 simulations of primordial black hole formation during radiation domination",
  "title_text": "Long-term 3+1 simulations of primordial black hole formation during radiation domination",
  "type": "preprint",
  "updated_at": "2026-10-30T12:18:31Z",
  "url": "https://research.draconitic.com/paper/eyx12v5r0ev2d",
  "venue": "arXiv",
  "versions": []
}