Topological acoustics is an emerging field that lies at the intersection of condensed matter
physics, mechanical structural design and acoustics engineering. It explores the design and …

The topological properties of an object, associated with an integer called the topological
invariant, are global features that cannot change continuously but only through abrupt …

The concept of topological energy bands and their manifestations have been demonstrated
in condensed matter systems as a fantastic paradigm toward unprecedented physical …

Metamaterials and phononic crystals (PCs) with artificially designed periodic microstructures
have attracted increasing research interests due to their unique properties that cannot be …

The emergence of a fractal energy spectrum is the quintessence of the interplay between
two periodic parameters with incommensurate length scales. crystals can emulate such …

Modern technological advances allow for the study of systems with additional synthetic
dimensions. Higher-order topological insulators in topological states of matters have been …

We present a theoretical study and experimental realization of a system that is
simultaneously a four-dimensional (4D) Chern insulator and a higher-order topological …

We propose and experimentally demonstrate the first example of Chern fractal insulators in
an acoustic Sierpinski lattice. Through introducing fractality into the well-known Haldane …

We experimentally demonstrate temporal pumping of elastic waves in an electromechanical
waveguide. Temporal pumping exploits a virtual dimension mapped to time, enabling the …

Research on breaking time-reversal symmetry to realize one-way wave propagation is a
growing area in photonic and phononic crystals and metamaterials. In this Letter, we present …