CANONICAL DEMON MONTE-CARLO RENORMALIZATION-GROUP

We describe a new method to compute renormalized coupling constants in a Monte Carlo renormalization group calculation. The method can be us ed for a general class of models, e.g., lattice spin or gauge models. The basic idea is to simulate a joint system of block spins and canoni cal demons. In contrast to the Microcanonical Renormalization Group in vented by Creutz et al. our method does not suffer from systematical e rrors stemming from a simultaneous use of two different ensembles. We present numerical results for the O(3) nonlinear sigma-model.