{
  "abstract": "Coupling gauge fields to the inflaton can amplify their quantum fluctuations during inflation, with potential applications to a range of cosmological phenomena. A central challenge is to define finite and physically meaningful observables, such as the gauge-field energy density. In this work, we study an Abelian gauge field kinetically coupled to the inflaton through $f^2(ϕ)F_{μν}F^{μν}$ in a de Sitter background with $f\\propto a^{γ_1}$, and compare conventional quantum-field-theoretic regularization with horizon-cutoff prescriptions. Using a hard physical-momentum cutoff and dimensional regularization, we derive the ultraviolet divergences in closed form and fix the remaining one-parameter finite-part ambiguity by requiring the coupling-induced total energy density to be nonnegative. We then examine five horizon-cutoff prescriptions based on characteristic scales of the mode equations. Their predictions depend sensitively on the choice of horizon scale and, for weak gauge-field production, can deviate substantially from the regularized result; for the adopted finite-part prescription, the minimal horizon agrees best with the regularized total energy density. As $|γ_1|\\to 2$, where infrared modes dominate, the relative deviation of all prescriptions from the regularized result vanishes, independently of the finite-part prescription. Outside this regime, the separate electric and magnetic contributions, which can become negative after regularization, are not reliably reproduced by any of the horizon-cutoff prescriptions.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.32599",
  "author_total": 3,
  "authors": [
    {
      "name": "A. O. Naidenko"
    },
    {
      "name": "O. O. Sobol"
    },
    {
      "name": "S. I. Vilchinskii"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/5p9xq8s6wgr36.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.32599",
  "fulltext_url": null,
  "id": "5p9xq8s6wgr36",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.32599",
  "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"
    ],
    [
      "arxiv",
      "hep-th"
    ],
    [
      "openalex",
      "3103|Cosmology and Gravitation Theories"
    ]
  ],
  "openalex": "W7223667397",
  "pdf_url": "https://arxiv.org/pdf/2610.32599",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-23",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/5p9xq8s6wgr36.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:35:15Z",
      "native_id": "2610.32599",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.32599"
    }
  ],
  "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": "Gauge-field energy density in inflationary kinetic-coupling models: QFT regularization versus horizon cutoffs",
  "title_text": "Gauge-field energy density in inflationary kinetic-coupling models: QFT regularization versus horizon cutoffs",
  "type": "preprint",
  "updated_at": "2026-10-30T12:35:15Z",
  "url": "https://research.draconitic.com/paper/5p9xq8s6wgr36",
  "venue": "arXiv",
  "versions": []
}