Experimental Demonstration of Dynamic Topological Pumping Across Incommensurate Bilayered Acoustic Metamaterials

TL;DR

This paper demonstrates a novel topological energy transfer in a dynamically driven acoustic metamaterial, showcasing edge mode pumping that enables energy transfer across the system in a way analogous to quantum Hall effects.

Contribution

It presents the first experimental demonstration of unassisted dynamic energy transfer via topological edge modes in an acoustic crystal with a driven aperiodic structure.

Findings

Edge modes enable energy transfer across the metamaterial.

Topological forbidden frequency range allows energy pumping.

Energy transfer is absent in non-topological conditions.

Abstract

A Thouless pump can be regarded as a dynamical version of the integer quantum Hall effect. In a finite-size configuration, such topological pump displays edge modes that emerge dynamically from one bulk-band and dive into the opposite bulk-band, an effect that can be reproduced with both quantum and classical systems. Here, we report the first un-assisted dynamic energy transfer across a metamaterial, via pumping of such topological edge modes. The system is a topological aperiodic acoustic crystal, with a phason that can be fast and periodically driven in adiabatic cycles. When one edge of the metamaterial is excited in a topological forbidden range of frequencies, a microphone placed at the other edge starts to pick up a signal as soon as the pumping process is set in motion. In contrast, the microphone picks no signal when the forbidden range of frequencies is non-topological.