RANDOM-WALKS WITH SHORT-RANGE INTERACTION AND MEAN-FIELD BEHAVIOR

We introduce a model of self-repelling random walks where the short-range interaction between two elements of the chain decreases as a power of the difference in proper time. The model interpolates between the lattice Edwards model and the ordinary random walk. We show by means of Monte Carlo simulations in two dimensions that the exponent nu(MF) obtained through a mean-field approximation correctly describes the numerical data and is probably exact as long as it is smaller than the corresponding exponent for self-avoiding walks. We also compute the exponent gamma and present a numerical study of the scaling functions.