Counting Yang-Mills Instantons by Surface Operator Renormalization Group Flow

We show that the nonperturbative dynamics of N=2 super-Yang-Mills theories in a self-dual ω background and with arbitrary simple gauge group is fully determined by studying renormalization group equations of vacuum expectation values of surface operators generating one-form symmetries. The corresponding system of equations is a nonautonomous Toda chain, the time being the renormalization group scale. We obtain new recurrence relations which provide a systematic algorithm computing multi-instanton corrections from the tree-level one-loop prepotential as the asymptotic boundary condition of the renormalization group equations. We exemplify by computing the E6 and G2 cases up to two instantons.