The world of superstuff

New Scientist (p30)

For centuries, con artists have convinced the masses that it is possible to defy gravity or walk through walls... But these are all cheap tricks compared with what the real world has to offer. Cool a piece of metal or a bucket of helium to near absolute zero and, in the right conditions, you will see the metal levitating above a magnet, liquid helium flowing up the walls of its container or solids passing through each other. "We love to observe these phenomena in the lab," says Ed Hinds [Physics] of Imperial College London... From these strange phenomena we can tease out all of chemistry and biology, find deliverance from our energy crisis and perhaps even unveil the ultimate nature of the universe... Though superfluids and superconductors are bizarre enough, they are not the limit of the quantum world's weirdness, it seems. "There is yet another level of complexity," says Ed Hinds. That complexity comes into play below 1 kelvin and at more than 25 times Earth's atmospheric pressure, when helium becomes a solid. This form of helium plays havoc with our notions of solidity. Get the conditions right and you can make solids pass through each other like ghosts walking through walls.

http://www.newscientist.com/article/mg21328476.700-superstuff-when-quantum-goes-big.html