{
  "abstract": "Recently, it has been proposed that the classical effective action of bosonic string theory should contain only couplings with an even number of tachyon fields. We employ the T-duality procedure to derive such couplings at order \\(α'\\) (four-derivative order) for the tachyon and massless fields. We first observe that, through higher-derivative field redefinitions of the tachyon potential term, one can choose a scheme in which, apart from the tachyon potential itself, all remaining couplings involve only covariant derivatives of the tachyon and the massless fields. We then construct a minimal basis of such couplings at four-derivative order, consisting of 14 independent terms. Imposing T-duality reduces this set to 6 nonzero couplings, expressed in terms of two unfixed parameters. One of these parameters is determined by matching to the known effective action in the zero-tachyon limit, while the other is fixed by comparison with the sphere-level S-matrix element of four tachyon vertex operators. This latter comparison also establishes that the coefficient of the \\(T^4\\) term in the tachyon potential is positive. Remarkably, the tachyon mass term and this quartic term are consistent with a potential of the form \\((2/α')(-1+\\cos T)\\), which implies that the closed string tachyon condenses to the minimum of the potential at \\(T=π\\), thereby generating an Anti-de Sitter spacetime with cosmological constant \\(Λ=-4/α'\\).",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.07221",
  "author_total": 1,
  "authors": [
    {
      "name": "Mohammad R. Garousi"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/6w5eaqpn9jakv.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.07221",
  "fulltext_url": null,
  "id": "6w5eaqpn9jakv",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.07221",
  "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",
      "hep-th"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2609.07221",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-23",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/6w5eaqpn9jakv.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:23:56Z",
      "native_id": "2609.07221",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.07221"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:hep-th",
      "subfield": "high-energy"
    }
  ],
  "title": "Tachyon-massless couplings at order $α'$ in bosonic string theory",
  "title_text": "Tachyon-massless couplings at order α' in bosonic string theory",
  "type": "preprint",
  "updated_at": "2026-10-30T12:23:56Z",
  "url": "https://research.draconitic.com/paper/6w5eaqpn9jakv",
  "venue": "arXiv",
  "versions": []
}