Acoustic resonances in open systems, which are usually associated with resonant modes
characterized by complex eigenfrequencies, play a fundamental role in manipulating …

Dissipation in mechanics, optics, acoustics, and electronic circuits is nowadays recognized
to be not always detrimental but can be exploited to achieve non-Hermitian topological …

Willis coupling generically stems from bianisotropy or chirality in wave systems.
Nevertheless, those schemes are naturally unavailable in diffusion systems described by a …

Acoustic metasurfaces are at the frontier of acoustic functional material research owing to
their advanced capabilities of wave manipulation at an acoustically vanishing size. Despite …

Willis materials exhibit macroscopic cross-coupling between particle velocity and stress as
well as momentum and strain. However, Willis coupling coefficients designed so far are …

Waves are generally characterized by angular frequency ω and wavevector k. Accordingly,
this tutorial is structured into two parts, one on resonance-based acoustic metamaterials, in …

Non-Newtonian liquids are characterized by stress and velocity-dependent dynamical
response. In elasticity, and in particular, in the field of phononics, reciprocity in the equations …

Guided waves, elastic waves propagating through bounded structures, play a pivotal role in
various applications, including ultrasonic non-destructive testing and structural health …

Recently, higher-order topologies have been experimentally realized, featuring topological
corner modes (TCMs) between adjacent topologically distinct domains. However, they have …

The phenomenon of retroreflection of light characterized by a single transversely polarized
wave has been extensively explored. However, the phenomenon of retroreflection of a …