English

Comments on Celestial CFT and $AdS_{3}$ String Theory

High Energy Physics - Theory 2026-05-15 v2

Abstract

In a recent work, Ogawa et al. (2024) proposed a model for celestial conformal field theory (CFT) based on the H3+H_{3}^{+}-Wess-Zumino-Novikov-Witten (WZNW) model. In this paper, we extend the model advanced by Ogawa et al. (2024), demonstrating how it can holographically generate tree-level MHV scattering amplitudes for both gluons and gravitons when analytically continued to the ultra-hyperbolic Klein space R22\mathbf{R}_{2}^{2}, thereby offering an alternative to celestial Liouville theory. We construct a holographic dictionary in which vertex operators and conformal primaries in celestial CFT are derived from their worldsheet counterparts in Euclidean AdS3AdS_{3} (bosonic) string theory. Within this dictionary, we derive the celestial stress-energy tensor, compute the two- and three-point functions, and determine the celestial operator product expansion (OPE). Additionally, we derive a system of partial differential equations that characterises the celestial amplitudes of our model, utilising the Knizhnik--Zamolodchikov (KZ) equations and worldsheet Ward identities. In the Appendix, we provide a concise introduction to the H3+H_{3}^{+}-WZNW model, with emphasis on its connection to Euclidean AdS3AdS_{3} string theory.

Keywords

Cite

@article{arxiv.2410.02620,
  title  = {Comments on Celestial CFT and $AdS_{3}$ String Theory},
  author = {Igor Mol},
  journal= {arXiv preprint arXiv:2410.02620},
  year   = {2026}
}

Comments

In the revised version, we have: improved the treatment of helicity and the definitions of celestial vertex operators; clarified the role of the boundary Virasoro central charge; and outlined how a forthcoming manuscript will describe celestial loop amplitudes

R2 v1 2026-06-28T19:07:14.749Z