Low-density series expansions for directed percolation: III. Some two-dimensional lattices

We introduce a model for temporally disordered directed percolation in which the probability of spreading from a vertex (t, x), where t is the time and x is the spatial coordinate, is independent of x but depends on t. Using a very efficient algorithm we calculate low-density series for bond percolation on the directed square lattice. Analysis of the series yields estimates for the critical point pc and various critical exponents which are consistent with a continuous change of the critical parameters as the strength of the disorder is increased. PACS numbers: 05.50.+q, 05.10.−a 1