Transients in a one-dimensional probabilistic cellular automaton

The characteristics of the distribution of transient times of a one-dimensional probabilistic cellular automaton are studied by computer simulation. The mean and width of the distribution are found to diverge by the same power-law at each of the two critical points, pc1 = 0 and pc2 0.75, of the model. Critical exponents obtained from finite-size scaling indicate that pc1 belongs to the universality class of directed random walks whereas pc2 belongs to the universality class of directed percolation. Between the two critical points there exists a point of minimum transient length at pm 0.23 where the mean transient time scales logarithmically with the system size.