Figure 1
From: Quantum random walks on congested lattices and the effect of dephasing

(a) The variance versus time t for the CRW and QRW on a two-dimensional square lattice defined by
. The rate of spreading is quadratic for the QRW and linear for the CRW. (b) The escape probability
against time for the CRW and QRW on a two-dimensional square lattice defined by
with a boundary defined by
. In the quantum case, the probability of escape is significantly larger for any given time after escaping than in the CRW.