Critical transport and vortex dynamics in a thin atomic Josephson junction

We study the onset of dissipation in an atomic Josephson junction between Fermi superfluids in themolecular Bose-Einstein condensation limit of strong attraction. Our simulations identify the criticalpopulation imbalance and the maximum Josephson current delimiting dissipationless and dissipativetransport, in quantitative agreement with recent experiments. We unambiguously link dissipation to vortexring nucleation and dynamics, demonstrating that quantum phase slips are responsible for the observedresistive current. Our work directly connects microscopic features with macroscopic dissipative transport,providing a comprehensive description of vortex ring dynamics in three-dimensional inhomogeneousconstricted superfluids at zero and finite temperatures.