{
  "abstract": "Hydrodynamic fluctuations in the primordial plasma generate a gravitational-wave (GW) background that grows like $f^3_\\mathrm{\\scriptscriptstyle 0}$ in terms of the current frequency. However, within the ($10^{-4}_{ } ... 10^4_{ })\\,$Hz band of upcoming interferometers, the modes likely re-entered the Hubble horizon when the hydrodynamic noise was no longer at its maximal value. To address this situation, we define a model-independent transfer function for GWs generated by hydrodynamic (or other white-noise) fluctuations at any time. Employing appropriate variables, we show how this transfer function, together with the simpler vacuum one, can be determined numerically for a general expansion history. The results are illustrated for Standard Model embedded warm inflation scenarios, including both the vacuum and hydrodynamic parts. Following previous estimates, we find that a pre-exit-generated hydrodynamic tail becomes almost flat below $(10^5_{ } ... 10^7_{ })\\;$Hz. Its small-$f^{ }_\\mathrm{\\scriptscriptstyle 0}$ intercept remains finite, and can then moderately influence observational constraints through the tensor-to-scalar ratio ($r$).",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.19500",
  "author_total": 2,
  "authors": [
    {
      "name": "Simone Biondini"
    },
    {
      "name": "M. Laine"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/de2e8ghy4fvjp.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.19500",
  "fulltext_url": null,
  "id": "de2e8ghy4fvjp",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.19500",
  "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",
      "gr-qc"
    ],
    [
      "arxiv",
      "hep-ph"
    ],
    [
      "openalex",
      "3103|Cosmology and Gravitation Theories"
    ]
  ],
  "openalex": "W7221966757",
  "pdf_url": "https://arxiv.org/pdf/2610.19500",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-14",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/de2e8ghy4fvjp.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:29:31Z",
      "native_id": "2610.19500",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.19500"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:gr-qc",
      "subfield": "gravitation"
    },
    {
      "field": "physics",
      "origin": "arxiv:hep-ph",
      "subfield": "high-energy"
    }
  ],
  "title": "Superhorizon enhancement of the hydrodynamic GW tail in Standard Model embedded warm inflation",
  "title_text": "Superhorizon enhancement of the hydrodynamic GW tail in Standard Model embedded warm inflation",
  "type": "preprint",
  "updated_at": "2026-10-30T12:29:31Z",
  "url": "https://research.draconitic.com/paper/de2e8ghy4fvjp",
  "venue": "arXiv",
  "versions": []
}