A mysterious particle has been discovered inside a superconducting crystal, more than 60 years after it was first predicted. The particle, called Pines’s demon, could explain why some materials superconduct, meaning they have zero electrical resistance, and help guide the search for new superconducting materials.
The particle is a type of plasmon, so-called because it arises from a collection of charged particles called a plasma. Such plasmas can form when electrons float freely from an atom, like in metallic materials. Plasmons are…