Universality Classes for Spreading Phenomena: A New Model with Fixed Static but Continuously Tunable Kinetic Exponents

A new and quite tractable model for spreading phenomena is proposed, which contains as a special case the Eden model and a model for epidemics. Two exponents are defined, one static and one kinetic ("growth"). The surprising feature is that the kinetic exponent can be continuously tuned while the static one does not change. Thus the dynamic universality classes are quite independent of the static one. This is the first one-cluster growth model showing dynamic universality classes unrelated to static ones and thereby yields insight into a generic feature for growth models.