Convergence of continuous-time quantum walks on the line

Phys Rev E Stat Nonlin Soft Matter Phys. 2005 Oct;72(4 Pt 2):047102. doi: 10.1103/PhysRevE.72.047102. Epub 2005 Oct 25.

Abstract

The position density of a "particle" performing a continuous-time quantum walk on the integer lattice, viewed on length scales inversely proportional to the time , converges (as tends to infinity) to a probability distribution that depends on the initial state of the particle. This convergence behavior has recently been demonstrated for the simplest continuous-time random walk [N. Konno, Phys. Rev. E 72, 026113 (2005)]. In this Brief Report, we use a different technique to establish the same convergence for a very large class of continuous-time quantum walks, and we identify the limit distribution in the general case.