  Unlike many particle systems, Activated Random Walk has nontrivial behavior
even in one spatial dimension. We prove inner and outer bounds on the spread of
n activated random walkers from a single source in Z. The inner bound involves
a comparison with the stationary distribution of activated random walkers on a
finite interval, while the outer bound involves a comparison with the
stabilization of an infinite Bernoulli configuration of activated random
walkers on Z.
