Seamus Davis, Cornell University
Although focus upon this material has diminished, superfluid Helium-3 (3He) remains by far the best-understood unconventional superconductor (superfluid). Moreover, it has recently re-emerged as a system of great theoretical interest because it is the only known odd-parity ‘topological' superfluid. In this reincarnation, it is a candidate for study of the zero-energy Bogoliubov states at superfluid boundaries since they can be viewed as ‘Majorana’ fermions. These states are of interest for their own properties and possibly for non-Abelian quantum computation. We review the implementation of superfluid circuitry and devices, and the known macroscopic quantum phenomena of superfluid 3He which are governed by topology. This includes circulation quantization, Josephson effects and the superfluid 3He quantum interference devices. Finally, we introduce and discuss some of the proposals for new studies of topological superfluidity and especially for Majorana fermion surface states, using superfluid 3He.