Nanowerk  May 18, 2023 The conventional mechanical metamaterials with inner resonators are characterized as homogenized solids with symmetric effective mass density tensors to interpret subwavelength wave attenuation mechanism. A team of researchers at the University of Missouri has presented a class of active metamaterials described by an odd mass density tensor which is no longer symmetric and whose nonzero asymmetric part arises from active and nonconservative forces. The unconventional wave phenomena caused by the odd mass density were demonstrated experimentally and numerically. The directional wave amplification was also illustrated by controllable feed-forward electric circuits. According to the researchers their findings […]