Impossible Matter: Supersolids by Brian Simpson

The League is always pleased to keep readers up-to-date with exciting scientific developments, well, at least those that I find interesting. Like “impossible” matter.
One recent paper, one of two, shows how to create matter which simultaneous has the properties of both a fluid and a solid is J. Li (et al.), “A Striped Phase with Supersolid Properties in Spin-Orbit-Coupled Bose-Einstein Condensates,” Nature, March 2, 2017. Unfortunately, you may not be able to create these weird quantum states in your kitchen, or out the back in the tool shed.

Cutting to the chase, Bose-Einstein condensates are a fifth state of matter, where atoms at super-cold temperatures begin to act like waves. Superfluids exist in ultra-cold states, near absolute zero, and have zero viscosity, flowing with no loss of kinetic energy. When stirred a superfluid continues to rotate indefinitely. Cool, eh?

A solid structure that could act like a superfluid could have a revolutionary impact on materials science, giving us “liquid metal,” best seen in the Terminator movies featuring killer shape-changing robots. But, there may be more innocent uses. In any case, this example shows that what we take to be a given, that something is either a solid or a liquid, is not necessarily so.