Topological sound pumping of zero-dimensional bound states

TL;DR

This paper demonstrates topological sound pumping using zero-dimensional bound states in acoustic systems, revealing new ways to control sound through topological phenomena like vortex-induced states and spectral flow.

Contribution

It introduces an acoustic analog of the Jackiw-Rossi vortex that exhibits Thouless pumping and maps vortex chirality to a 2D quantum-Hall system for sound.

Findings

Spectral flow of corner states merges with Majorana-like states.

Chirality maps into a 2D quantum-Hall system with sonic hotspots.

Provides new tools for sound control using topological effects.

Abstract

Topological phases have spurred unprecedented abilities for sound, light and matter engineering and recent progress has shown how waves not only confine at the interfaces between topologically distinct insulators, but in the form of zero-dimensional non-propagating states bound to defects or corners. Majorana-like bound states have recently been observed in man-made Kekul\'e textured lattices. We show here how the acoustic version of the associated Jackiw-Rossi vortex embodies a Thouless pumping process, in which the spectral flow of corner states adiabatically merge with the said Majorana-like state. Moreover, we argue how the chirality of the Kekul\'e vortex additionally maps into a 2D quantum-Hall system comprising spatially separated sonic hotspots. We foresee that our findings should provide novel exotic tools to enable contemporary control over sound.