Physics Guy@physicsguyPhysicists have found evidence that electrons in cuprate superconductors pair up before the material becomes superconducting. They reached this by listening to the electrical noise in the current, since paired electrons make more noise than single ones.
The extra noise rose right at the energy of the pseudogap, the state where some electrons seem to vanish. The team says this suggests the pairs form first and only later move in step, which is where the bottleneck to superconductivity lies.
