Observation of an acoustic topological Euler insulator with meronic waves

• DOI: 10.1016/j.scib.2024.04.009
• Publication Date: 2024-04-04T16:42:25Z
• Authors: Bin Jiang; Adrien Bouhon; Shi-Qiao Wu; Ze-Lin Kong; Zhi-Kang Lin; Robert-Jan Slager; Jian-Hua Jiang
• Keywords: Topological insulator; Euler characteristic; Brillouin zone

Topological band theory has conventionally been concerned with the topology of bands around a single gap. Only recently non-Abelian topologies that thrive on involving multiple gaps were studied, unveiling new horizon in topological physics beyond conventional paradigm. Here, we report first experimental realization Euler insulator phase unique meronic characterization an acoustic metamaterial. We demonstrate this several nontrivial features: First, system cannot be described by theory, but class captures unconventional geometry Bloch Brillouin zone. Second, uncover and probe experiments configuration bulk states for time. Third, using detailed symmetry analysis, show evolves from semimetal via annihilation Dirac points pairs one gaps. With these properties, establish concretely bulk-edge correspondence which is confirmed directly measuring edge pump-probe techniques. Our work thus unveils pattern paves way as platform phenomena.