| Weyl points have many exotic properties,such as chirality anomaly and topological Fermi arc surface states.Many researchers have devoted themselves to exploring Weyl physics in synthetic space,as it is very difficult to explore Weyl points in real space,especially in terms of making samples and measuring experimental data.Hence,many researchers have begun to explore Weyl physics in synthetic space.The main contexts of this article are as follows:1.Studying Weyl physics in one-dimensional layered sonic crystals.In this work,we report one-dimensional layered sonic crystals that exhibit many exotic properties.In this acoustic system these are synthetic Weyl points and their reflection phase have a vortex structure.The nontrivial interface states,accompanying local-field enhancements,are also exhibited.Furthermore,we predict that the nodal lines in synthetic parameter space in simulations.2.Exploring topological rainbow devices associated with acoustic valley Hall insulators in synthetic space.In this section,a rotational degree of freedom is introduced to construct synthetic 3-dimensional space.In this synthetic space,there are Weyl points,Fermi arcs and topologically nontrivial edge modes.Not only rotational operation,but also boundary truncation modulate the frequencies of nontrivial edge states,which result in two completely different edge states at the upper and lower boundaries,respectively.Using frequency characteristic of edge states,we devise two different acoustic topological rainbow devices.Two devices can both trap the acoustic waves with different frequency at different spatial positions,for low frequency acoustic waves that can travel very far in one device and very close in the other.This work may boost further the development of topological rainbow devices in synthetic space related to acoustic valley Hall insulator. |
