Automorphism Modular Invariants of Current Algebras

TL;DR

This paper classifies all possible partition functions of a specific class of two-dimensional rational conformal field theories with affine Kac--Moody algebra symmetry, identifying spectra and primary fields with minimal quantum dimensions.

Contribution

It provides a complete classification of automorphism modular invariants for current algebra RCFTs based on simple Lie algebras.

Findings

Classified all automorphism modular invariants for simple Lie algebra-based current algebras.

Determined the spectra of these RCFTs.

Identified primary fields with second smallest quantum dimension.

Abstract

We consider those two-dimensional rational conformal field theories (RCFTs) whose chiral algebras, when maximally extended, are isomorphic to the current algebra formed from some affine non-twisted Kac--Moody algebra at fixed level. In this case the partition function is specified by an automorphism of the fusion ring and corresponding symmetry of the Kac--Peterson modular matrices. We classify all such partition functions when the underlying finite-dimensional Lie algebra is simple. This gives all possible spectra for this class of RCFTs. While accomplishing this, we also find the primary fields with second smallest quantum dimension.