In the paper Chiral Koszul duality, Gaitsgory and Francis develop a notion of a chiral algebra living on an arbitrary variety $X$. When $X=\mathbf{A}^1$ and the chiral algebra is translation invariant, this reproduces the usual notion of a vertex algebra.
I'm interested in getting a picture about what can/has been said about chiral algebras one dimension up, when $X$ is a surface. For instance,
- The notion of vertex algebra reappears throughout physics, e.g. in conformal field theory. Does the higher dimensional analogue appear in physics naturally?
- There is an interesting relation between loop spaces/affine Grassmannian and vertex algebras, e.g. via the WZW vertex algebra $V_k(\mathfrak{g})$. Is there any interesting relation between the higher dimensional vertex algebras and say the double loop space, which as I understand it is an even more interesting object?