{
  "abstract": "We investigate how future high-precision neutron star (NS) radius measurements encode microscopic information about the dense-matter equation of state (EOS), focusing on a possible first-order hadron--quark phase transition and the resulting mass--radius topology. Within a Bayesian framework using meta-model EOSs with nine microscopic parameters, we analyze mock radius measurements $R_{1.4}=11.9\\pmσ_R$ km with $σ_R=0.9$ and $0.1$ km for canonical NSs. We introduce inverse EOS--radius mappings by studying the conditional mean of each EOS parameter as a function of the model-predicted canonical radius $R_{1.4}$. Their slope measures the sensitivity of an EOS parameter to the radius, while their curvature determines the leading precision dependence of its posterior mean through the Jensen expansion. The symmetry-energy parameters $L$ (slope) and $K_{\\rm sym}$ (curvature) are strongly encoded in $R_{1.4}$ and their posterior means shift appreciably with improved radius precision, whereas the higher-order hadronic parameters show stronger topology dependence. Among the transition parameters, the transition density $ρ_t$ is the most strongly encoded in $R_{1.4}$, while the energy-density jump and quark-matter sound speed are more strongly associated with the topology of the full mass--radius sequence. Since the different topologies have strongly overlapping $R_{1.4}$ distributions, even precise radius measurements cannot by themselves identify the topology or uniquely determine the high-density transition properties. These results provide a parameter-dependent hierarchy for assessing the scientific return of future high-precision radius measurements and complementary probes of high-density NS EOS.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": "Journal reference: The Astrophysical Journal, 1011:215 (2026)",
  "arxiv": "2608.12632",
  "author_total": 2,
  "authors": [
    {
      "name": "Bao-An Li"
    },
    {
      "name": "Xavier Grundler"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/6sd3bgntmhgwe.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2608.12632",
  "fulltext_url": null,
  "id": "6sd3bgntmhgwe",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2608.12632",
  "language": null,
  "licence": "CC0-1.0",
  "licence_label": "CC0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/publicdomain/zero/1.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "astro-ph.HE"
    ],
    [
      "arxiv",
      "hep-ph"
    ],
    [
      "arxiv",
      "nucl-ex"
    ],
    [
      "arxiv",
      "nucl-th"
    ],
    [
      "openalex",
      "3103|Pulsars and Gravitational Waves Research"
    ]
  ],
  "openalex": "W7203443901",
  "pdf_url": "https://arxiv.org/pdf/2608.12632",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-28",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/6sd3bgntmhgwe.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:25:31Z",
      "native_id": "2608.12632",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2608.12632"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.HE",
      "subfield": "high-energy-astrophysics"
    },
    {
      "field": "physics",
      "origin": "arxiv:hep-ph",
      "subfield": "high-energy"
    },
    {
      "field": "physics",
      "origin": "arxiv:nucl-ex",
      "subfield": "nuclear"
    }
  ],
  "title": "How Neutron Star Radii Encode the Dense-Matter Equation of State and Hadron-Quark Transition",
  "title_text": "How Neutron Star Radii Encode the Dense-Matter Equation of State and Hadron-Quark Transition",
  "type": "preprint",
  "updated_at": "2026-11-09T00:20:13Z",
  "url": "https://research.draconitic.com/paper/6sd3bgntmhgwe",
  "venue": "arXiv",
  "versions": [
    {
      "doi": "10.3847/1538-4357/aeae2c",
      "pid": "1n9wq8hqhkx9h",
      "relation": "published-as",
      "title": "How Neutron Star Radii Encode the Dense-matter Equation of State and Hadron–Quark Transition",
      "venue": "The Astrophysical Journal"
    }
  ]
}