Helical Anomaly from Concurrent $\mathbb{Z}$ and ${\mathbb{Z}}_2$ Topology in an Acoustic Semimetal

Hou-Yin Li, Hua-Shan Lai, Jian-Lan Xie +3

Topological classification constitutes a cornerstone of modern condensed-matter physics. Historically, topological systems have been predominantly characterized by invariants confi…