A review is given on the foundations and applications of non-Hermitian classical and
quantum physics. First, key theorems and central concepts in non-Hermitian linear algebra …

Acoustic metamaterials can manipulate and control sound waves in ways that are not
possible in conventional materials. Metamaterials with zero, or even negative, refractive …

Metamaterials are rationally designed composites aiming at effective material parameters
that go beyond those of the ingredient materials. For example, negative metamaterial …

Within a time span of 15 years, acoustic metamaterials have emerged from academic
curiosity to become an active field driven by scientific discoveries and diverse application …

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 …

Negative refraction of elastic waves has been studied and experimentally demonstrated in
three-and two-dimensional phononic crystals, but Bragg scattering is impractical for low …

The coupling of waves between the piezoelectric generators, detectors, and propagating
media is challenging due to mismatch in the acoustic properties. The mismatch leads to the …

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

Manipulating the properties of the isofrequency contours (IFCs) of materials provides a
powerful means of controlling the interaction between light and matter. Hyperbolic …