{
  "abstract": "Conventional Fermi-liquid theories of dense nuclear matter predict that the direct Urca process requires a proton fraction above a threshold of $Y_p \\approx 0.11$--$0.15$, which is rarely reached in low-mass neutron stars. Here we show that this stringent kinematic constraint is drastically relaxed by the non-Fermi liquid behavior arising from superfluid and superconducting quantum criticality in neutron stars. In the non-Fermi-liquid regimes, nucleons have a smooth momentum occupation without a sharp Fermi surface, and their chemical potentials develop a logarithmic temperature dependence. These intrinsic features fundamentally alter the standard $β$-equilibrium relation. Consequently, direct Urca neutrino emission can be activated even at low nuclear densities. This modifies the long-standing Urca-threshold paradigm and indicates that direct Urca process has the opportunity to occur in low-mass neutron stars.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.28023",
  "author_total": 2,
  "authors": [
    {
      "name": "Hao-Fu Zhu"
    },
    {
      "name": "Guo-Zhu Liu"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/9jcyny0n4ektw.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.28023",
  "fulltext_url": null,
  "id": "9jcyny0n4ektw",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.28023",
  "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",
      "cond-mat.str-el"
    ],
    [
      "arxiv",
      "nucl-th"
    ],
    [
      "openalex",
      "3103|Pulsars and Gravitational Waves Research"
    ]
  ],
  "openalex": "W7223095786",
  "pdf_url": "https://arxiv.org/pdf/2610.28023",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-20",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/9jcyny0n4ektw.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:34:04Z",
      "native_id": "2610.28023",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.28023"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.HE",
      "subfield": "high-energy-astrophysics"
    },
    {
      "field": "physics",
      "origin": "arxiv:cond-mat.str-el",
      "subfield": "condensed-matter"
    },
    {
      "field": "physics",
      "origin": "arxiv:nucl-th",
      "subfield": "nuclear"
    }
  ],
  "title": "Direct Urca process facilitated by non-Fermi-liquid quantum criticality",
  "title_text": "Direct Urca process facilitated by non-Fermi-liquid quantum criticality",
  "type": "preprint",
  "updated_at": "2026-10-30T12:34:04Z",
  "url": "https://research.draconitic.com/paper/9jcyny0n4ektw",
  "venue": "arXiv",
  "versions": []
}