Non-critical superstrings from four-dimensional gauge theory

We study large-N double-scaling limits of U( N) gauge theories in four dimensions. We focus on theories in a partially confining phase where an abelian subgroup G of the gauge group remains unconfined. Double-scaling is defined near critical points in the parameter/moduli space where states charged under G become massless. In specific cases, we present evidence that the double-scaled theory is dual to a non-critical superstring background. Models studied include the beta-deformation of N = 4 SUSY Yang-Mills which leads to a non-critical string theory with sixteen supercharges. We also study N = 1 SUSY Yang-Mills theory coupled to a single chiral superfield with a polynomial superpotential which leads to a related string theory with eight supercharges. In both cases the string coupling is small and the background is free from Ramond-Ramond flux.