Universal Behavior of Quantum Walks with Long-Range Steps

Abstract

Quantum walks with long-range steps $R^{-\gamma}$ ($R$ being the distance between sites) on a discrete line behave in similar ways for all $\gamma\geq2$. This is in contrast to classical random walks, which for $\gamma >3$ belong to a different universality class than for $\gamma \leq 3$. We show that the average probabilities to be at the initial site after time $t$ as well as the mean square displacements are of the same functional form for quantum walks with $\gamma=2$, 4, and with nearest neighbor steps. We interpolate this result to arbitrary $\gamma\geq2$.