Criticality in a model with absorbing states - art. no. 026105

We study a one-dimensional model that undergoes a transition between an act ive and an absorbing phase. Monte Carlo simulations supported by some addit ional arguments prompted us to predict the exact location of the critical p oint and critical exponents in this model. The exponents delta = 0.5 and z = 2 follows from random-walk-type arguments. The exponents beta = nu (perpe ndicular to) are found to be nonuniversal and encoded in the singular part of reactivation probability, as recently discussed by H. Hinrichsen (cond-m at/0008179). A related model with quenched randomness is also studied.