Journal of Statistical Physics, Vol. 55, Nos. 5/6, 1989 p. 1285-1292.
The question whether diffusion in the hard-square lattice gas is blocked in the
thermodynamic limit is mapped to the problem whether percolation occurs in
the time evolution of a cellular automaton. The final states of the cellular
automaton are investigated for varying lattice sizes from 6x6 up to
20,035x20,032. The results seem to indicate that there is a percolation
threshold, i.e., a range of concentrations for which diffusion is blocked.
However, since this cannot be true for the infinite system, as proven rigorously,
it is concluded that finite-size effects persist for this system up to very large sizes.