Giant fluctuations of topological charge in a disordered wave guide

TL;DR

This paper investigates how disorder and boundaries in a wave guide cause large fluctuations in the total topological charge of scalar waves, especially near cut-off frequencies where screening is suppressed.

Contribution

It provides new insights into the behavior of topological charge fluctuations in disordered wave guides, highlighting the impact of boundaries and scattering on screening effects.

Findings

Fluctuations of topological charge are significantly enhanced near wave guide cut-off frequencies.

Boundary effects strongly suppress screening, leading to large charge fluctuations.

Fluctuations are highly sensitive to the level of disorder in the wave guide.

Abstract

We study the fluctuations of the total topological charge of a scalar wave propagating in a hollow conducting wave guide filled with scatterers inside. We investigate the dependence of the screening on the scattering mean free path and on the presence of boundaries. Near the cut-off frequencies of the wave guide, screening is strongly suppressed near the boundaries. The resulting huge fluctuations of the total topological charge are very sensitive to the disorder.