Consider a discrete time quantum walk on a 2-dimensional square lattice, with particles starting from point A and detected at point B. To establish an efficient channel for transport from A to B, which links (edges) in the lattice should you remove? We show that the counterintuitive strategy of picking a path that connects A and B, and removing links that cross this path, can create such a channel, that uses topologically protected edge states . The existence of these edge states depends on the bulk properties of the quantum walk (including topological invariants other than the Chern number ), and on the way the links are removed (similarly to 1D quantum walks ), but not on the precise shape of the path. The channel ensures a transmission probability independent of the distance of A and B, even in the presence of static disorder, which induces Anderson localization. Time-dependent disorder, however, causes decoherence and thus makes the channel lossy.
 T. Kitagawa, Quant. Inf. Proc. 1570-0755 (2012); arXiv:1112.1882
 M. S. Rudner, N. H. Lindner, E. Berg, M. Levinot, arXiv:1212.3324 (2012)
 J. K. Asboth, Phys. Rev. B 86, 195414 (2012)