AGT relations for abelian quiver gauge theories on ALE spaces

TL;DR

This paper establishes a mathematical framework connecting the geometry of moduli spaces of sheaves on ALE spaces with affine Kac-Moody algebra representations, proving the AGT correspondence for certain abelian gauge theories.

Contribution

It constructs explicit representations of affine Kac-Moody algebras on moduli space cohomologies and proves the AGT correspondence for pure and superconformal abelian quiver gauge theories on ALE spaces.

Findings

Representation of $\u00afhat{rak{gl}}_k$ on cohomology spaces

Proof of AGT correspondence for pure $U(1)$ gauge theory on $X_k$

Proof of AGT correspondence for abelian superconformal quiver theories

Abstract

We construct level one dominant representations of the affine Kac-Moody algebra $\widehat{\mathfrak{gl}}_k$ on the equivariant cohomology groups of moduli spaces of rank one framed sheaves on the orbifold compactification of the minimal resolution $X_k$ of the $A_{k-1}$ toric singularity $\mathbb{C}^2/\mathbb{Z}_k$. We show that the direct sum of the fundamental classes of these moduli spaces is a Whittaker vector for $\widehat{\mathfrak{gl}}_k$, which proves the AGT correspondence for pure $\mathcal{N}=2$ $U(1)$ gauge theory on $X_k$. We consider Carlsson-Okounkov type Ext-bundles over products of the moduli spaces and use their Euler classes to define vertex operators. Under the decomposition $\widehat{\mathfrak{gl}}_k\simeq \mathfrak{h}\oplus \widehat{\mathfrak{sl}}_k$, these vertex operators decompose as products of bosonic exponentials associated to the Heisenberg algebra $\mathfrak{h}$ and primary fields of $\widehat{\mathfrak{sl}}_k$. We use these operators to prove the AGT correspondence for $\mathcal{N}=2$ superconformal abelian quiver gauge theories on $X_k$.