Weight representations of affine Kac-Moody algebras and small quantum groups

Abstract

We study the weight modules over affine Kac-Moody algebras from the view point of vertex algebras, and determine the abelian category of weight modules for the simple affine vertex algebra $L_k({\mathfrak{sl}}_2)$ at any non-integral admissible level $k$. In particular, we show that the principal block of the category of weight modules over admissible $L_k({\mathfrak{sl}}_2)$ is equivalent to that of the corresponding (unrolled) small quantum group.