Point gap is signature of non-Hermitian systems, but the experimental identification of nontrivial point gaps is elusive. Here, the authors use a Weyl phononic crystal to demonstrate that the point gap constituted by bulk and Fermi-arc surface states can be observed experimentally by a real-space field mapping technique and discover various skin effects and their evolutions.
- Riyi Zheng
- Jing Lin
- Zhengyou Liu
