{
  "abstract": "We systematically investigate and compare the worldsheet actions, BRST structures and the quantum anomalies of four different formulations of tensionless ($T = 0$) bosonic string theory: the $(D+2)$-dimensional conformal string \\cite{Gustafsson:1994kr}, the $D$-dimensional ILST null string \\cite{Isberg:1993av}, the $D$-dimensional Carroll-Weyl gauged string \\cite{Sheikh-Jabbari:2026vqh, Sheikh-Jabbari:2026tpf}, and the $D$-dimensional hybrid null string \\cite{Chen:2026klv}. By expressing all fields and constraint generators strictly in terms of mode expansions and adopting a unified algebraic framework, we analyze their quantum anomalies under two distinct worldsheet vacua: the induced vacuum and the flipped vacuum. With the BRST-compatible vacuum definition and the symmetric $α=0$ zeta prescription, we show that no critical dimension is inferred from the vanishing of the quantum anomaly in the induced vacuum. In contrast, the flipped highest-weight vacuum leads to non-trivial constraints, reproducing the critical dimension $D=26$ for the ILST null strings, a $λ$-dependent critical dimension $D(λ)$ for the hybrid null string whose range covers every positive integer $D\\geq 4$ (reproduces $D=26$ at $λ=1$), and more importantly showing that the conformal string and the Carroll-Weyl gauged string are structurally anomalous with no consistent critical dimension due to the discrepancy of their central charge parameters $\\tilde d_i$. Furthermore, the ILST null string model has target-space conformal symmetry $SO(D,2)$, the ghost-completed $SO(D,2)$ charges are closed on the induced-vacuum BRST cohomology in the $α=0$ prescription, whereas the symmetry is quantum mechanically broken in the flipped vacuum.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2608.02987",
  "author_total": 2,
  "authors": [
    {
      "name": "Bin Chen"
    },
    {
      "name": "Zezhou Hu"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/dkg3crt0fw3wm.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2608.02987",
  "fulltext_url": null,
  "id": "dkg3crt0fw3wm",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2608.02987",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "hep-th"
    ],
    [
      "openalex",
      "3106|Black Holes and Theoretical Physics"
    ]
  ],
  "openalex": "W7172519007",
  "pdf_url": "https://arxiv.org/pdf/2608.02987",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-15",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/dkg3crt0fw3wm.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:29:50Z",
      "native_id": "2608.02987",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2608.02987"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:hep-th",
      "subfield": "high-energy"
    }
  ],
  "title": "Quantum Anomalies of Tensionless Bosonic Strings",
  "title_text": "Quantum Anomalies of Tensionless Bosonic Strings",
  "type": "preprint",
  "updated_at": "2026-10-30T12:29:50Z",
  "url": "https://research.draconitic.com/paper/dkg3crt0fw3wm",
  "venue": "arXiv",
  "versions": []
}