This image shows two states of a cuprate high-temperature superconductor simultaneously:
Each circle represents the two electrons of a Cooper pair, which exist at relatively low energy and can carry current with no resistance. In this image, the superconducting Cooper-pair state is superimposed on a dashed pattern that indicates the static positions of electrons caught in a quantum "traffic jam" at higher energy - when the material acts as a Mott-insulator incapable of carrying current. (Click on the image to download a high-resolution version.)
Last Modified: November 9, 2009
