{
  "abstract": "Hawking's area theorem states that the total event-horizon area of classical black holes can never decrease. Gravitational-wave tests of this law have so far focused on individual loud mergers, thus probing only a sparse subset of binary parameter space. Here we perform the \\emph{first} population-level test. We exploit the decomposition of the coalescing black holes in the latest gravitational-wave catalogue into a low-spin subpopulation of stellar-collapse origin and a high-spin subpopulation assembled through hierarchical mergers of the former. If the high-spin black holes are merger remnants, the area theorem requires their horizon areas to exceed the total pre-merger areas of the low-spin binaries. Using parameter estimation restricted to the inspiral of 241 events, so that no merger-ringdown information enters the inference, we find that both peaks of the horizon-area distribution of second-generation black holes lie above their first-generation counterparts. The displacement is significant at each peak ($2.1$--$3.7σ$), and when we tie the two subpopulations with a single common shift, an area decrease is excluded decisively ($\\gtrsim5.0σ$). The second law of black-hole mechanics thus holds statistically across the quasicircular, moderately spinning mergers that dominate current catalogues, which in turn underpins the robustness of our classification of stellar-collapse and hierarchical-merger black holes.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2608.16563",
  "author_total": 3,
  "authors": [
    {
      "name": "Shao-Peng Tang"
    },
    {
      "name": "Yin-Jie Li"
    },
    {
      "name": "Yi-Zhong Fan"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/1q514z19x0mva.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2608.16563",
  "fulltext_url": null,
  "id": "1q514z19x0mva",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2608.16563",
  "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.HE"
    ],
    [
      "arxiv",
      "gr-qc"
    ],
    [
      "openalex",
      "3103|Pulsars and Gravitational Waves Research"
    ]
  ],
  "openalex": "W7203718693",
  "pdf_url": "https://arxiv.org/pdf/2608.16563",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-07",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/1q514z19x0mva.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:19:48Z",
      "native_id": "2608.16563",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2608.16563"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.HE",
      "subfield": "high-energy-astrophysics"
    },
    {
      "field": "physics",
      "origin": "arxiv:gr-qc",
      "subfield": "gravitation"
    }
  ],
  "title": "Population-Level Verification of the Black-Hole Area Law with First- and Second-Generation Black Holes",
  "title_text": "Population-Level Verification of the Black-Hole Area Law with First- and Second-Generation Black Holes",
  "type": "preprint",
  "updated_at": "2026-10-30T12:19:48Z",
  "url": "https://research.draconitic.com/paper/1q514z19x0mva",
  "venue": "arXiv",
  "versions": []
}