MICROCANONICAL RENORMALIZATION-GROUP SIMULATION OF ISING SYSTEMS

We report the results of a microcanonical simulation of the two- and t hree-dimensional Ising models at criticality. We also present a microc anonical algorithm that allows a simultaneous simulation of a lattice spin system at different energies, in our case the number of different energies is 32. The critical behavior of the systems was studied via a recently proposed microcanonical renormalization-group technique tha t yields independent estimates for the critical energy and the critica l temperature, as well as for three critical exponents providing a dir ect test of hyperscaling. Our results in two dimensions are in good ag reement with exact results. In three dimensions our quoted values are consistent with Monte Carlo estimates recently reported in the literat ure. We obtain u(c) = -0.991(1), T(c) = 4.5112(3), beta/nu = 0.541(1), nu = 0.630(3), and alpha = 0.109(1).