Medium-range percolation in two dimensions

We investigate equivalent-neighbor percolation models in two dimensions with a variable interaction range, and include the mean-field limit. We employ a Monte Carlo algorithm whose efficiency depends only weakly on the number of equivalent neighbors within the range of the interactions. We consider 2 classes of models, one in which the interacting neighbors fill a circle, and one in which they fill a square. We first determine the critical points, and then determine the critical exponents. These are, for all finite ranges investigated, in agreement with the exactly known exponents of the nearest-neighbor model.