Random Matrices and Quantum Spin Chains

Random matrix ensembles are introduced that respect the local tensor structure of Hamiltonians describing a chain of n distinguishable spin-half particles with nearest-neighbour interactions. We prove a central limit theorem for the density of states when n -> infinity, giving explicit bounds on the rate of approach to the limit. Universality within a class of probability measures and the extension to more general interaction geometries are established. The level spacing distributions of the Gaussian Orthogonal, Unitary and Symplectic Ensembles are observed numerically for the energy levels in these ensembles.