Critical branching random walk in an IID environment

Abstract

Using a high performance computer cluster, we run simulations regarding an open problem aboutd -dimensional critical branching random walks in a random IID en- vironment The environment is given by the rule that at every site independently, with probability p 2 Œ0;1� , there is a cookie, completely suppressing the branching of any particle located there. The simulations suggest self averaging: the asymptotic survival probability inn steps is the same in the annealed and the quenched case; it is 2 qn ,w hereq WD1� p. This particular asymptotics indicates a non-trivial phenomenon: the tail of the survival probability (both in the annealed and the quenched case) is the same as in the case of non-spatial unit time critical branching, where the branching rule is modified: branching only takes place with probabilityq for every particle at every iteration.