Nonrational conformal field theory
J. Teschner
TL;DR
The work argues for extending conformal-field-theory mathematics beyond rational models by developing a gluing-based framework for conformal blocks on general Riemann surfaces and a stable, unitary modular functor. It emphasizes a holomorphic factorization of correlation functions, a canonical Hermitian form on block spaces, and a careful treatment of moduli-space boundary behavior via gluing, all aimed at enabling harmonic-analysis-like methods on block spaces. The Virasoro nonrational example (c>25) is used to illustrate genus-zero blocks, free-field realizations, and factorization, while outlining how unitary fusion and modular geometry could underpin a generalized Verlinde-like structure. The paper sketches how W-algebras, Langlands duality, and boundary CFT fit into this nonrational paradigm, suggesting deep connections to automorphic-harmonic analysis and potential new invariants beyond the classical Verlinde formula.
Abstract
We discuss the problem to develop a mathematical theory of a certain class of nonrational conformal field theories (CFT) which contain the unitary CFT. A variant of the concept of a modular functor is proposed that appears to be suitable for such CFT.
