Demonstration of a Third Order Hierarchy of Higher-Order Topological States in a Three-Dimensional Acoustic Metamaterial

M. Weiner, X. Ni, M. Li, A. Alù, and A. Khanikaev. Demonstration of a Third Order Hierarchy of Higher-Order Topological States in a Three-Dimensional Acoustic Metamaterial. under review, since January 2019. (arxiv)