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 study of classical wave physics has been reinvigorated by incorporating the concept of
the geometric phase, which has its roots in optics, and topological notions that were …

Phononic crystals (PCs) and metamaterials (MMs) can exhibit abnormal properties, even far
beyond those found in nature, through artificial design of the topology or ordered structure of …

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

In solid state physics, a bandgap (BG) refers to a range of energies where no electronic
states can exist. This concept was extended to classical waves, spawning the entire fields of …

Recently, we witnessed a tremendous effort to conquer the realm of acoustics as a possible
playground to test with topologically protected sound wave propagation. In this article, we …

Topological mechanical metamaterials have emerged with the development of topological
phases and topological phase transitions in modern condensed matter physics. Their …

Topological elastic metamaterials have emerged as a new frontier in the quest of topological
phases in condensed matter physics. Their exotic topological properties open a wealth of …

The recent emergence of topological insulators in condensed matter physics has inspired
analogous wave phenomena in mechanical systems. However, to date, the design of these …

In this work, we experimentally report the acoustic realization of the two-dimensional Su-
Schrieffer-Heeger model in a simple network of air channels. We analytically study the …