Large-N Limit of N=2 Supersymmetric QN Model in Two Dimensions

We investigate non-perturbative structures of the two-dimensional N=2supersymmetric nonlinear sigma model on the quadric surface Q^{n-2}(C) =SO(n)/SO(n-2)xU(1), which is a Hermitian symmetric space, and therefore Kahler,by using the auxiliary field and large-n methods. This model contains two kindsof non-perturbatively stable vacua; one of them is the same vacuum as that ofsupersymmetric CP^{n-1} model, and the other is a new kind of vacuum, which hasnot yet been known to exist in two-dimensional nonlinear sigma models, theHiggs phase. We show that both of these vacua are asymptotically free. Althoughsymmetries are broken in these vacua, there appear no massless Nambu-Goldstonebosons, in agreement with Coleman's theorem, due to the existence of twodifferent mechanisms in these vacua, the Schwinger and the Higgs mechanisms.Comment: LaTeX, 28 pages, 22 figures, published versio