Hilbert Schemes of Points in the Plane and Quasi-Lisse Vertex Algebras with $\mathcal{N}=4$ Symmetry

To each complex reflection group $\Gamma$ one can attach a canonical symplectic singularity $\mathcal{M}_\Gamma$ arXiv:math/9903070. Motivated by the 4D/2D duality arXiv:1312.5344, arXiv:1707.07679, Bonetti, Meneghelli and Rastelli arXiv:1810.03612 conjectured the existence of a supersymmetric vertex operator superalgebra $\mathsf{W}_\Gamma$ whose associated variety is isomorphic to $\mathcal{M}_\Gamma$. We prove this conjecture when the complex reflection group $\Gamma$ is the symmetric group $S_N$ by constructing a sheaf of $\hbar$-adic vertex operator superalgebras on the Hilbert scheme of $N$ points in the plane. For that case, we also show the free-field realisation of $\mathsf{W}_\Gamma$ in terms of $\operatorname{rk}(\Gamma)$ many $\beta\gamma bc$-systems proposed in arXiv:1810.03612, and identify the character of $\mathsf{W}_\Gamma$ as a certain quasimodular form of mixed weight and multiple $q$-zeta value. In physical terms, the vertex operator superalgebra $\mathsf{W}_{S_N}$ constructed in this article corresponds via the 4D/2D duality arXiv:1312.5344 to the four-dimensional $\mathcal{N}=4$ supersymmetric Yang-Mills theory with gauge group $\operatorname{SL}_N$.