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Quantum levitation

I know, I know. You’ve seen this. I’m slow to the party. But you know what? You can go to hell. This is too awesome not to put on The Black Laser.


It’s Okay to Be Smart has a description of how it works:

What you start with is an inert disc, in this case a crystal sapphire wafer. That wafer is then coated with a superconductor called yttrium barium copper oxide. When superconductors get very cold (like liquid nitrogen cold) they conduct electricity with no loss of energy, which normal conducting materials like copper can’t do.

Superconductors hate magnetic fields (when cold enough), and normally would just repel the magnetic force and float in a wobbly fashion. But because the superconductor is so thin in this case, tiny imperfections allow some magnetic forces through. These little magnetic channels are called flux tubes:

The flux tubes cause the magnetic field to be “locked” in all three dimensions, which is why the disk remains in whatever position it starts in, levitating around the magnets.

Drier explanations here and here.

Charles sent me this video the other day and the thing we started talking about immediately was whether or not the floating would decay over time or if the super cooled slug would just fall when it warmed up so much that it was no longer able to maintain the quantum lock. And then we recognized that we were total nerds, but you knew that already, didn’t you?