Jiasen Niu

A layer of electrons trapped between two semiconductor plates lines up into a neat lattice at low temperatures, like beads on a string stretched between your fingers. As the temperature rises, order collapses: the crystal melts. But exactly how it melts has long been a puzzle.

Current flowing through a wire is never perfectly smooth. If you listen closely enough, you hear a rustle — shot noise. It arises because charge is not carried as a continuous stream but in discrete portions, like raindrops on a roof. From the character of this noise, you can tell how much charge each 'drop' carries.