Two physicists in China have shown that it should be possible to observe negative refraction with sound waves. Xiangdong Zhang of Beijing Normal University and Zhengyou Liu of Wuhan University have ...

Scientists have created a new class of laser beam that appears to violate long-held laws of light physics. These new beams, which the team calls “spacetime wave packets,” follow different rules of ...

The interface between two facets of an artificial material known as a “Weyl phononic crystal” can not only negatively refract an airborne sound wave, it does so without reflecting it at all. This ...