Critical Transport and Vortex Dynamics in a Thin Atomic Josephson Junction.

Area of Science:

• Atomic physics
• Quantum condensed matter physics
• Superfluidity

Background:

• Atomic Josephson junctions are crucial for studying quantum transport.
• Understanding dissipation in superfluids is key to controlling quantum devices.
• The molecular Bose-Einstein condensation limit presents unique challenges for superfluid dynamics.

Purpose of the Study:

• To investigate the onset of dissipation in an atomic Josephson junction.
• To identify critical parameters delimiting dissipationless and dissipative transport.
• To link microscopic vortex dynamics to macroscopic resistive current.

Main Methods:

• Numerical simulations of Fermi superfluids in the strong attraction limit.
• Analysis of critical population imbalance and maximum Josephson current.
• Identification of vortex ring nucleation and dynamics as the source of dissipation.

Main Results:

• Simulations quantitatively agree with recent experimental findings.
• Dissipation is unambiguously linked to vortex ring nucleation and dynamics.
• Quantum phase slips are identified as the cause of resistive current.

Conclusions:

• Microscopic features are directly connected to macroscopic dissipative transport.
• A comprehensive description of vortex ring dynamics in inhomogeneous superfluids is provided.
• The study offers insights into quantum transport and dissipation in superfluids.