Large-N limit of N=2 supersymmetric Q(N) model in two dimensions

We investigate non-perturbative structures of the two-dimensional N = 2 sup ersymmetric nonlinear sigma model on the quadric surface Q(N-2)(C) = SO(N)/ SO(N-2) x U(1), which is a Hermitian symmetric space, and therefore Kahler, by using the auxiliary field and large-N methods. This model contains two kinds of non-perturbatively stable vacua; one of them is the same vacuum as that of the supersymmetric CPN-1 model, and the other is a new kind of vac uum, which has not yet been known to exist in two-dimensional nonlinear sig ma models, the Higgs phase. We show that both of these vacua are asymptotic ally free. Although symmetries are broken in these vacua, there appear no m assless Nambu-Goldstone bosons, in agreement with Coleman's theorem, dye to the existence of two different mechanisms in these vacua, the Schwinger an d the Higgs mechanisms.