Intersecting Surface Operators in 6d Holomorphic Field Theories

We study intersecting surface operators in 6d holomorphic field theories with the aim of unraveling associated quantum integrable structures. We first study the intersections of surface operators in 6d holomorphic Chern-Simons theory on $\mathbb{C}^3$. Computing their correlation function, we find a local operator at the intersection of the surface operators with a form reminiscent of the leading nontrivial term in the quasi-classical expansion of a rational $R$-matrix, as predicted by Costello. We provide evidence that this $R$-matrix-like operator satisfies a Yang-Baxter-type relation. We then derive the associated coproduct of the chiral algebra supported by surface operators from their OPE. We also study intersecting surface operators in 6d holomorphic BF theory and derive the local leading form of the corresponding $R$-matrix-like operator. When this theory is placed on twistor space, where it describes the self-dual sector of 4d Yang-Mills theory, this operator is expected to provide a local building block for quantum integrable structures anticipated in that setting.