{
  "abstract": "We study the closed-string tree-level Virasoro-Shapiro amplitude using the dispersive S-matrix bootstrap. For the ten-dimensional maximally supersymmetric four-point amplitude, we impose analyticity, crossing symmetry, partial-wave unitarity, and Regge boundedness. With the massless graviton pole kept explicitly, the resulting dispersion relations and crossing null constraints give numerical bounds on the leading low-energy coefficients normalized by the gravitational coupling, which agree at our reference truncation with earlier bounds from smeared functionals. We then introduce a Virasoro-inspired ansatz, which becomes a set of nonlinear relations among Wilson coefficients and shrinks the allowed region toward the Virasoro-Shapiro trajectory. Finally, we study a gravity-pole-subtracted setup, where the regular part of the amplitude has a well-defined forward limit. In this stripped problem, on the slice of the leading coefficient that places the first Virasoro-Shapiro resonance at the cutoff, the nonlinear constraints reduce the allowed region to a small island containing the Virasoro-Shapiro point. Imposing the ansatz to all orders, together with spectral assumptions not used in the numerics, we show analytically that positivity selects the Virasoro-Shapiro spectrum.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2606.19283",
  "author_total": 1,
  "authors": [
    {
      "name": "Yongjun Xu"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/cpjmj8gj5j327.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2606.19283",
  "fulltext_url": null,
  "id": "cpjmj8gj5j327",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2606.19283",
  "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",
      "3106|Black Holes and Theoretical Physics"
    ]
  ],
  "openalex": "W7165186165",
  "pdf_url": "https://arxiv.org/pdf/2606.19283",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-16",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/cpjmj8gj5j327.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:30:32Z",
      "native_id": "2606.19283",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2606.19283"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:hep-th",
      "subfield": "high-energy"
    }
  ],
  "title": "A Dispersive Bootstrap for the Virasoro-Shapiro Amplitude",
  "title_text": "A Dispersive Bootstrap for the Virasoro-Shapiro Amplitude",
  "type": "preprint",
  "updated_at": "2026-10-30T12:33:28Z",
  "url": "https://research.draconitic.com/paper/cpjmj8gj5j327",
  "venue": "arXiv",
  "versions": []
}