XY CHAIN WITH RANDOM ANISOTROPY - MAGNETIZATION LAW, SUSCEPTIBILITY, AND CORRELATION-FUNCTIONS AT T = O

The random-anisotropy model in one dimension, at zero temperature, is studied analytically and in Monte Carlo simulations, focusing on the magnetization curve as a function of disorder strength D, and on the susceptibility and correlation functions. The predicted scaling of the susceptibility (for weak disorder), chi is-proportional-to D-4/3, is verified, as is the prediction \M-1\ is-proportional-to H-3/2 on approaching saturation. The correlation length does not follow the expected behavior, R(f) is-proportional-to D-2/3. Nonequilibrium effects are evident: Hysteresis persists even for small disorder, and (steady-state) correlation functions depend strongly upon the initial state of the system. A new simulation method is introduced, which is more effective than the usual Metropolis algorithm for weak disorder.