Journal of Statistical Physics Vol. 76, Nos. 5/6, 1994, p. 1377-1398.
We investigate the dynamics of ensembles of diffusive defects in one-dimensional
deterministic cellular automata. The work builds on earlier results on individual
random walks in cellular automata. Here we give a natural condition guarantee-
ing diffusive behavior also in the presence of other defects. Simple branching
and birth mechanisms are introduced and prototype classes of cellular automata
exhibiting weakly interacting walks capable of annihilation and coalescence are
studied. Their equilibrium behavior is also characterized. The design principles
of cellular automata with desired diffusive interaction properties become trans-
parent from this analysis.