The discovery of topological phases has introduced new perspectives and platforms for
various interesting physics originally investigated in quantum contexts and then, on an equal
footing, in classic wave systems. As a characteristic feature, nontrivial Fermi arcs, connecting
between topologically distinct Fermi surfaces, play vital roles in the classification of Dirac
and Weyl semimetals, and have been observed in quantum materials very recently.
However, in classical systems, no direct experimental observation of Fermi arcs in …

The discovery of topological phases introduces new perspectives and platforms for various
interesting physics originally investigated in quantum context and then, on an equal footing,
in classic wave systems, such as photonics, acoustics and mechanics. As a characteristic
feature, nontrivial Fermi arcs, connecting between topologically distinct Fermi surfaces, play
vital roles in the clarification of Dirac and Weyl semimetals and have been observed in
quantum materials very recently. However, in classical systems, no direct experimental …