On the large N convergence of matrix models

Abstract

In this paper, the large N behavior of a supersymmetric matrix model is compared with its exact continuum description. We concentrate on the large N limit of a supersymmetric matrix model describing a supermembrane with central charge on a toroidally compactified target space. We analyze, on the one hand, the supermembrane model formulated on a differentiable compact torus without boundary, with structure group given by the area-preserving diffeomorphisms, and, on the other hand, the associated regularized $SU(N)$ model. We emphasize in our analysis the structure of the constraints of the regularized model, which generate the $SU(N)$ algebra and reproduce the area-preserving diffeomorphism algebra in the large N limit, together with the topological information associated with the central charge of the model. We explain the role of the central charge in the compactified supermembrane and how it allows a top-down $SU(N)$ regularization. It is known that the regularized model has discrete spectrum. We prove, in the semiclassical approximation of the models, that in the large N limit the eigenvalues of the Hamiltonian of the supersymmetric matrix model are in one to one correspondence with, and converge exactly to, the eigenvalues of the Hamiltonian of the supermembrane (M2-brane) with central charge. Finally, we discuss some physical consequences of this result.