Temporally disordered bond percolation on the directed square lattice

Simple models of directed bond percolation with temporal disorder are introduced and studied via series expansions and Monte Carlo simulations. Series have been derived for the percolation probability on the directed square lattice. Analysis of the series revealed that the critical exponent beta and critical point p(c) change continuously with the strength of the disorder. Monte Carlo simulation confirmed the continuous change of critical exponents. Estimates for the temporal correlation-length exponent nu(parallel to) for weak disorder showed that nu(parallel to) < 2 in apparent violation of the Harris criterion.