Superfluidity in helium 3: Nobel colloquium

Prof. Robert C. Richardson "The Discovery of Superfluid 3He" Superfluid 3He was found through an accident. The transition was discovered in some pioneering cryogenic experiments and was originally mis-identified as the state of nuclear magnetic order in solid 3He. Subsequent NMR experiments, including an early version of MRI, revealed that liquid 3He undergoes a surprising pairing transition. The superfluid state is similar to superconducting state in metals but with an odd value of the pair angular momentum. The cryogenic techniques and early experiments will be described. Prof. Doug D. Osheroff "Superfluidity in 3He: The Discovery Through the Eyes of a Graduate Student" The speaker will recount the activities during a seven month period in which, as a graduate student, he participated in the discovery of three superfluid phases of liquid 3He. At the time, this discovery was the 'holy grail' of low temperature physics, yet, even after the final experiment, the three researchers were reluctant to identify these as BCS states, so unusual were the properties of the ordered states which they had observed. Prof. David M. Lee "Significance of Superfluid Helium 3 Research to Other Branches of Science" The superfluid phases of liquid helium 3 are important examples of non s-wave BCS pairing. The order parameters of these more complex pairing states possess internal degrees of freedom which lead to collective mode and soliton phenomena in addition to ordinary superfluid behavior. The relation of superfluid helium 3 to other systems in which non s-wave pairing plays a role will be discussed. Examples include high temperature superconductivity, heavy Fermion superconductivity and the interiors of neutron stars. The possible role of superfluid helium 3 as a model system for the early universe will be discussed briefly.