Inhibition of spreading in quantum random walks due to quenched Poisson-distributed disorder

TL;DR

This paper investigates how quenched Poisson-distributed disorder affects quantum random walks, revealing significant inhibition of spread and universal behavior across different jump distributions.

Contribution

It introduces a model of quantum walks with Poisson-distributed jumps and demonstrates the universal sub-ballistic, super-diffusive spreading behavior.

Findings

Walker spread is significantly inhibited by quenched Poisson disorder.

The dispersion scaling is sub-ballistic but super-diffusive.

Universal features are observed across sub- and super-Poissonian jump distributions.

Abstract

We consider a quantum particle (walker) on a line who coherently chooses to jump to the left or right depending on the result of toss of a quantum coin. The lengths of the jumps are considered to be independent and identically distributed quenched Poisson random variables. We find that the spread of the walker is significantly inhibited, whereby it resides in the near-origin region, with respect to the case when there is no disorder. The scaling exponent of the quenched-averaged dispersion of the walker is sub-ballistic but super-diffusive. We also show that the features are universal to a class of sub- and super-Poissonian distributed quenched randomized jumps.