Trapping a particle of a quantum walk on the line

TL;DR

This paper demonstrates that a phase change at a single point in a discrete quantum walk can induce localization, with the effect depending on the walker's internal coin state, revealing new control mechanisms.

Contribution

It introduces the phenomenon of phase-induced localization in quantum walks and explores its dependence on the coin state, a novel insight into quantum walk dynamics.

Findings

Phase change causes localization in quantum walks.

Localization depends on the internal coin state.

Certain phase values strongly enhance localization.

Abstract

We observe that changing a phase at a single point in a discrete quantum walk results in a rather surprising localization effect. For certain values of this phase change the possibility of localization strongly depends on the internal coin-state of the walker.