Quantum anomalies of tensionless bosonic strings
- 1Kunming University of Science and Technology
- 2Peking University
- 3Ningbo University
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 [1], the D-dimensional ILST null string [2], the D-dimensional Carroll-Weyl gauged string [3, 4], and the D-dimensional hybrid null string [5]. 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 ≥ 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 d̃i. 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.
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BibTeX
@article{chen2026quantum,
title = {{Quantum anomalies of tensionless bosonic strings}},
author = {Bin Chen and Zezhou Hu},
journal = {Journal of High Energy Physics},
year = {2026},
month = nov,
doi = {10.1007/jhep11(2026)040},
url = {https://link.springer.com/article/10.1007/JHEP11(2026)040},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Quantum anomalies of tensionless bosonic strings
AU - Bin Chen
AU - Zezhou Hu
PY - 2026
DA - 2026/11/05
JO - Journal of High Energy Physics
DO - 10.1007/jhep11(2026)040
UR - https://link.springer.com/article/10.1007/JHEP11(2026)040
AB - 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 [1], the D-dimensional ILST null string [2], the D-dimensional Carroll-Weyl gauged string [3, 4], and the D-dimensional hybrid null string [5]. 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 ≥ 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 d̃_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.
SN - 1029-8479
ER -