Acoustic Su-Schrieffer-Heeger lattice: Direct mapping of acoustic waveguides to Su-Schrieffer-Heeger model

TL;DR

This paper demonstrates a direct mapping of acoustic waveguides to the Su-Schrieffer-Heeger topological model, showing experimentally that topological edge modes are robust in audible acoustic systems.

Contribution

It provides a novel experimental realization of the SSH model using acoustic waveguides, bridging topological physics with audible acoustics.

Findings

Edge modes appear naturally due to boundary conditions and wavelength constraints.

Topological edge modes are robust against chiral disorder.

Experimental results confirm theoretical predictions in the audible regime.

Abstract

Topological physics strongly relies on prototypical lattice model with particular symmetries. We report here on a theoretical and experimental work on acoustic waveguides that is directly mapped to the one-dimensional Su-Schrieffer-Heeger chiral model. Starting from the continuous two dimensional wave equation we use a combination of monomadal approximation and the condition of equal length tube segments to arrive at the wanted discrete equations. It is shown that open or closed boundary conditions topological leads automatically to the existence of edge modes. We illustrate by graphical construction how the edge modes appear naturally owing to a quarter-wavelength condition and the conservation of flux. Furthermore, the transparent chirality of our system, which is ensured by the geometrical constraints allows us to study chiral disorder numerically and experimentally. Our experimental results in the audible regime demonstrate the predicted robustness of the topological edge modes.