{
  "abstract": "The Lyth bound asserts that the field excursion of inflaton must be sub-Planckian, thereby imposing an upper bound on the amplitude of the tensor power spectrum in inflationary scenario. This bound is conventionally derived assuming a scale-invariant curvature power spectrum, i.e., $n_s = 1$. However, astrophysical observations confirm a red-tilted spectrum with $n_s < 1$. In light of recent results from the Atacama Cosmology Telescope (ACT) DR6, we revisit these constraints using the newly implied scalar spectral index of $n_s \\simeq 0.9743$. Incorporating the ACT data yields a different upper bound on the tensor-to-scalar ratio $r$, which can potentially exclude inflationary scenarios previously robust under the original Lyth bound with $n_s = 1$. Our result highlights the urgent need to combine theoretical Lyth bound considerations with the most up-to-date astrophysical data.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": "Journal reference: Chinese Physics C 51, 015102 (2027)",
  "arxiv": "2606.16711",
  "author_total": 4,
  "authors": [
    {
      "name": "Rui Yang"
    },
    {
      "name": "Jun Tao"
    },
    {
      "name": "Peng Wang"
    },
    {
      "name": "Mian Zhu"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/anjnjaxehnxx4.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2606.16711",
  "fulltext_url": null,
  "id": "anjnjaxehnxx4",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2606.16711",
  "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"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2606.16711",
  "pmcid": null,
  "pmid": null,
  "published": "2026-11-04",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/anjnjaxehnxx4.ris",
  "sources": [
    {
      "first_seen": "2026-11-05T15:20:55Z",
      "native_id": "2606.16711",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2606.16711"
    }
  ],
  "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": "Revisiting the Lyth bound constraints on inflation from ACT DR6 results",
  "title_text": "Revisiting the Lyth bound constraints on inflation from ACT DR6 results",
  "type": "preprint",
  "updated_at": "2026-11-09T00:20:12Z",
  "url": "https://research.draconitic.com/paper/anjnjaxehnxx4",
  "venue": "arXiv",
  "versions": [
    {
      "doi": "10.1088/1674-1137/ae9b9c",
      "pid": null,
      "relation": "published-as",
      "title": null,
      "venue": null
    }
  ]
}