Scientists have officially discovered the first direct evidence that points towards the existence of the theorized Cooper pair density wave in superconductors. Confused yet? Wait, there's more.
The 1964 prediction stated that Cooper pairs of electrons could essentially exist in two states within superconductors. One state would be superfluid, where all particles move as a single entity in the same quantum state. The other, theorized state would see these Cooper pairs vary in density (that is, breaking away from their superfluid state). That latter state was dubbed, theoretically, a Cooper pair density wave.
The science goes way above my head, but the importance of the discovery is notable in that it could provide more insight into high-temperature superconductor. This evidence also indicates that electrons can exist in two states, something that wasn't considered possible at one time.
The evidence was found by scientists at the U.S. Department of Energy's Brookhaven National Laboratory, Cornell University, and collaborators, according to Science Bulletin. That article is also the source for the image you see at the head of this post. The image, according to Science Bulletin, represents the "periodic variation in the density of Cooper pairs (pairs of blue arrows pointing in opposite directions) within a cuprate superconductor." That's the discovery on hand.