||Quantum weirdness: Pictures of a BEC 'cloud' of sodium atoms in the NIST experiment to transfer rotational energy to a quantum system show the cloud (a) rotating in a donut-shaped vortex, and interfering with itself as the cloud (b) simultaneously rotates in opposite directions, and (c) simultaneously rotates and stands still. Rotational energy is transferred in quantized amounts. False-color images show (d) one and (e) two units of rotational motion.
*PHY, sodium atoms, Bose-Einstein condensates
See also http://www.nist.gov/public_affairs/techbeat/tb2006_1109.htm#tornado.