Acoustic Structure Could Evade Sonar

Materials called topological insulators conduct electricity only along their surfaces and have a range of potential uses. A team in Singapore has now proposed a structure that could do the same thing for sound waves, causing them to be guided in just one direction around the surface of a region and to ignore imperfections that would scatter the sound in an ordinary material. If it can be built, such a structure might find uses in acoustic technologies, such as soundproofing and sonar stealth systems.