Ward Identities in the sl₃ Toda Conformal Field Theory

Toda conformal field theories are natural generalizations of Liouville conformal field theory that enjoy an enhanced level of symmetry. In Toda conformal field theories this higher-spin symmetry can be made explicit, thanks to a path integral formulation of the model based on a Lie algebra structure. The purpose of the present document is to explain how this higher level of symmetry can manifest itself within the rigorous probabilistic framework introduced by R. Rhodes, V. Vargas and the first author in Cerclé (Probabilistic construction of simply-laced Toda conformal field theories, arXiv preprint, arXiv:2102.11219, 2021). One of its features is the existence of holomorphic currents that are introduced via a rigorous derivation of the Miura transformation. More precisely, we prove that the spin-three Ward identities, that encode higher-spin symmetry, hold in the sl₃ Toda conformal field theory; as an original input we provide explicit expressions for the descendent fields which were left unidentified in the physics literature. This representation of the descendent fields provides a new systematic method to find the degenerate fields of the sl₃ Toda (and Liouville) conformal field theory, which in turn implies that certain four-point correlation functions are solutions of a hypergeometric differential equation of the third order.