Superfluids are weird liquids that flow with no friction and can perform fantastic feats, such as spontaneously crawling over the walls of containers. Theorists have proposed that quantum-mechanical interactions among even a few atoms can give rise to such behaviors.
Now, researchers in Canada have evidence for the onset of superfluidity in a droplet containing a mere seven atoms of liquid helium-4. For now, isotopes of helium are the only substances known to exhibit superfluidity, which appears at temperatures just above absolute zero (SN: 9/23/00, p. 207: Available to subscribers at Hydrogen hoops give superfluid clues).
Wolfgang Jäger an