Holography for non-critical superstrings

We argue that a class of ''non-critical superstring'' vacua is holographically related to the (non-gravitational) theory obtained by studying string theory on a singular Calabi-Yau manifold in the decoupling limit gs→0. In two dimensions, adding fundamental strings at the singularity of the CY manifold leads to conformal field theories dual to a recently constructed class of AdS3 vacua. In four dimensions, special cases of the construction correspond to the theory on an NS5-brane wrapped around a Riemann surface. (author)