Topological acoustics

Topological acoustics is an emerging field that lies at the intersection of condensed matter physics, mechanical structural design and engineering. It explores construction novel artificial structures, such as acoustic metamaterials phononic crystals, to manipulate sound waves robustly, taking advantage topological protection. Early work on was limited duplicating phases have been understood in systems, but recent advances shifted exploring new concepts are difficult realize other physical various semimetal phases, associated with Floquet engineering, fragile topology, non-Hermiticity synthetic dimensions. These developments demonstrate unique advantages systems their role developing physics. In this Review, we survey fundamental mechanisms, basic designs practical realizations provide overview future directions potential applications. The introduction topology into platforms enables robust control. This Review discusses designs, promising for systems.