Topological sound pumping of zero-dimensional bound states

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 Kekulé textured lattices. It is shown here how the acoustic version of the associated Jackiw–Rossi vortex embodies a topological pumping process, in which the spectral flow of corner states adiabatically merge with the said Majorana‐like state. Moreover, it is argued how the chirality of the Kekulé vortex additionally maps into a 2D quantum‐Hall system comprising spatially separated sonic hotspots. It is foreseen that the findings should provide novel exotic tools to enable contemporary control over sound.