Consistent systems of correlators in non-semisimple conformal field theory

TL;DR

This paper defines consistent bulk field correlator systems in non-semisimple conformal field theories using modular functors, linking them to Frobenius algebras and extending rational CFT structures to logarithmic cases.

Contribution

It introduces a new framework for correlators in non-semisimple CFTs, connecting them to Frobenius algebra structures and generalizing rational CFT concepts.

Findings

Correlator systems correspond to commutative symmetric Frobenius algebras at genus zero.

For all genus surfaces, correlator systems correspond to modular Frobenius algebras.

Provides a bridge between rational and logarithmic conformal field theories.

Abstract

Based on the modular functor associated with a -- not necessarily semisimple -- finite non-degenerate ribbon category $\mathcal D$, we present a definition of a consistent system of bulk field correlators for a conformal field theory which comprises invariance under mapping class group actions and compatibility with the sewing of surfaces. We show that when restricting to surfaces of genus zero such systems are in bijection with commutative symmetric Frobenius algebras in $\mathcal D$, while for surfaces of any genus they are in bijection with modular Frobenius algebras in $\mathcal D$. This provides additional insight into structures familiar from rational conformal field theories and extends them to rigid logarithmic conformal field theories.