Nobel Lecture by Anthony J. Leggett (42 minutes)Anthony J. Leggett held his Nobel Lecture December 8, 2003, at Aula Magna, Stockholm University. He was presented by Professor Mats Jonson, Chairman of the Nobel Committee for Physics. Summary: Helium exists in two stable forms: the normal Helium-4 with two neutrons and two protons, and Helium-3 with one neutron and two protons. The two show very different superconducting properties at very low temperatures. The anomalous superfluidity of Helium-3 is explained using the principles of quantum mechanics. An analogy between ferro-magnets and liquid Helium-3 is used to explain the theory of superfluid Helium-3.   Credits: Kamera Communications (webcasting)