Suppressed Solitonic Cascade in Spin-Imbalanced Superfluid Fermi Gas

Area of Science:

• Atomic, Molecular, and Optical Physics
• Condensed Matter Physics
• Quantum Fluids

Background:

• Cold atom experiments provide insights into superfluid dynamics and topological defect decay cascades.
• Understanding these dynamics in Fermi superfluids, especially spin-imbalanced systems, is limited compared to Bose systems.
• Spin-imbalanced Fermi superfluids exhibit complex structures due to coexisting superfluid (paired) and normal (unpaired) components.

Purpose of the Study:

• To investigate the impact of spin polarization on the decay cascades of topological defects in Fermi superfluids.
• To elucidate the microscopic mechanisms governing these modified decay processes.
• To explore the consequences for phenomena like quantum turbulence.

Main Methods:

• Development and application of a novel microscopic approach.
• Theoretical modeling of topological defect decay in spin-polarized Fermi superfluids.
• Analysis of particle dynamics and spatial structures within the atomic cloud.

Main Results:

• Spin polarization dramatically modifies topological defect decay cascades.
• Decay cascades terminate at different stages (dark soliton, vortex ring, or vortex line) depending on spin polarization.
• Unpaired particles are drawn into the soliton's core, hindering vortex reconnections.

Conclusions:

• Spin polarization introduces new physics into Fermi superfluid dynamics.
• The observed modification of decay cascades and hindered vortex reconnections can significantly affect quantum turbulence.
• This work highlights the crucial role of spin polarization in controlling superfluid behavior.