Production of Feshbach molecules induced by spin-orbit coupling in Fermi gases

Abstract

The search for topological superconductors is a challenging task1,2. One of the most promising directions is to use spinorbit coupling through which an s-wave superconductor can induce unconventional p-wave pairing in a spin-polarized metal3,4. Recently, synthetic spin-orbit couplings have been realized in cold-atom systems5-16 where instead of a proximity effect, s-wave pairing originates from a resonant coupling between s-wave molecules and itinerant atoms17. Here we demonstrate a dynamic process in which spin-orbit coupling coherently produces s-wave Feshbach molecules from a fully polarized Fermi gas, and induces a coherent oscillation between these two. This demonstrates experimentally that spin-orbit coupling does coherently couple singlet and triplet states, and implies that the bound pairs of this system have a triplet p-wave component, which can become a topological superfluid by further cooling to condensation and confinement to one dimension.