Abstract

Wave transport in time-independent potentials is formally divided into two major categories depending on how the second moment of the evolving excitation grows with “time”. If translational symmetry is present, the eigenmodes of the system are plane waves or Floquet-Bloch modes [1], and the variance of an initially localized excitation increases quadratically in time (ballistic spreading). On the other hand, since the pioneering work of Anderson [2], it is known that disorder (at least in one-dimension) tends to suppress propagation and leads to localization [3]. In all cases, however, it is believed that the wave packet spreading is bounded in all times by that of a ballistic growth.

© 2013 IEEE