Two teams of physicists have independently created a mysterious new state of matter. The state is known as a supersolid and it combines the properties of both solid and superfluid states. Illustration of a supersolid state, in which the properties of a frictionless fluid and a crystalline state coincide. Image credit: Julian Léonard, ETH Zurich. Solid, liquid or gas — we encounter these three classic states of matter every day. It is difficult...
