{
  "abstract": "A bstract : We argue that the electromagnetic θ -term is a physical parameter of the Standard Model coupled to gravity. Specifically, in the context of 4-dimensional Einstein-Maxwell theory we show that there exist Euclidean field configurations that have finite action, are asymptotically flat, and feature non-zero electromagnetic second Chern number. These “gravitational Abelian instantons” correspond to a dyonic extension of a Euclidean wormhole. We argue that these configurations should be included in the gravitational path integral, and that doing so generates a non-perturbative contribution to the vacuum energy density that is θ -dependent. We provide a Lorentzian interpretation of these instantons as capturing the effect of quantum fluctuations corresponding to pair production and annihilation of charged black holes. When θ is the expectation value of a dynamical axion field, the instantons presented here generate a potential for the axion, thereby breaking the axion shift symmetry. This provides yet another example of how quantum gravity violates global symmetries through the existence of black holes.",
  "abstract_shown": true,
  "affiliations": [
    "University of Washington"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 2,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Isabel Garcia Garcia",
      "orcid": "0000-0001-8866-7376"
    },
    {
      "affs": [
        0
      ],
      "name": "Elliot Maderazo",
      "orcid": "0000-0001-5587-6876"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/83xef9bm03g1t.bib",
  "cited_by": 1,
  "doi": "10.1007/jhep10(2026)029",
  "fulltext_url": null,
  "id": "83xef9bm03g1t",
  "issns": [
    "1029-8479"
  ],
  "landing_url": "https://link.springer.com/10.1007/JHEP10(2026)029",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "3106|Black Holes and Theoretical Physics"
    ]
  ],
  "openalex": "W4417464932",
  "pdf_url": "https://link.springer.com/content/pdf/10.1007/JHEP10(2026)029.pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-02",
  "publisher": "Springer Science and Business Media LLC",
  "ris": "https://research.draconitic.com/paper/83xef9bm03g1t.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:01Z",
      "native_id": "10.1007/jhep10(2026)029",
      "source": "crossref",
      "url": "https://link.springer.com/10.1007/JHEP10(2026)029"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "openalex:3106|Black Holes and Theoretical Physics",
      "subfield": "high-energy"
    }
  ],
  "title": "Black holes and Abelian instantons",
  "title_text": "Black holes and Abelian instantons",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:18:01Z",
  "url": "https://research.draconitic.com/paper/83xef9bm03g1t",
  "venue": "Journal of High Energy Physics",
  "versions": []
}