Hao Zheng

At a temperature of 4.3 degrees above absolute zero, a crystal of palladium telluride stops resisting electric current. Electrons pair up and move without loss, like a crowd holding hands. But this superconductor seems to have not one but two different ways of pairing.

A flashlight beam in fog spreads out within a couple of meters. Light particles scatter in all directions, like a crowd in a square. But sometimes they can march in formation — without spreading, without mixing. That's exactly the kind of march achieved in a tiny perovskite crystal. The crystal was placed between two mirrors.