Physicists have found conclusive evidence for superfluidity-flow without resistrance in an ultracold Fermi gas. Although indirect evidence for superfluidityu in Fermi gases has been searching for definitive evidence in the form of quantized vortices in a rotating gas.Now Wolfgang Ketterle and colleagues at the Massachusetts Institute of Technology (MIT) have observed these vortices in a gas of lithium-6 atoms (Nature 435 1047). The results could shed new light on systems as dicerse as high-temperature superconductors and the quark-gluon plasma.
Physicists are getting closer and closer to the holy grail of research into ultracold atomic gases – the observation of superfluidity in a Fermi gas. Research groups in Austria and the US have recently taken a major step towards this goal by creating a Bose–Einstein condensate of bosonic molecules from a gas of fermionic atoms. If the atoms can be persuaded to form weakly bound pairs, rather than molecules, physicists hope to learn more about the basic mechanisms responsible for superconductivity.