Searching for Bloch wave packets with almost definite momentum direction
Phys. Rev. A 112, 032223 – Published 26 September, 2025
DOI: https://doi.org/10.1103/k9km-k3dm
Abstract
The motion of a quantum particle in a one-dimensional periodic potential can be described in terms of Bloch wave packets. Like free-particle wave packets, they can propagate without attenuation. Here, we examine this similarity more closely by investigating whether Bloch wave packets can maintain a definite—or nearly definite—momentum direction, a property inherent in free-particle wave packets. This question is particularly relevant to the feasibility of using solid-state-based systems in the search for the first experimental realization of quantum backflow, a quantum interference effect in which a particle's probability density flows in a direction opposite to its momentum.
