Geometric transitions and integrable systems

We consider B-model large N duality for a new class of noncompact Calabi-Yau spaces modeled on the neighborhood of a ruled surface in a Calabi-Yau threefold. The closed string side of the transition is governed at genus zero by an A(1) Hitchin integrable system on a genus g Riemann surface Sigma. The open string side is described by a holomorphic Chern-Simons theory which reduces to a generalized matrix model in which the eigenvalues lie on the compact Riemann surface Sigma. We show that the large N planar limit of the generalized matrix model is governed by the same A(1) Hitchin system therefore proving genus zero large N duality for this class of transitions.