Local conservation laws in ultracold Fermi systems with time-dependent interaction potential

Area of Science:

• Quantum physics
• Condensed matter physics

Background:

• Ultracold Fermi gases provide a tunable platform for studying quantum many-body phenomena.
• Understanding transport properties, like shear viscosity, is crucial for describing these systems.

Purpose of the Study:

• To derive general conservation laws for mass, energy, and momentum in ultracold Fermi gases.
• To investigate the role of gradient corrections and collision dynamics on these conservation laws.
• To analyze the impact of collision delay on shear viscosity.

Main Methods:

• Generalized nonlocal Boltzmann equation with gradient corrections.
• In-medium T matrix theory and variations of the optical theorem.
• Microscopic theory and comparison with the Nozières and Schmitt-Rink approach.

Main Results:

• Derived mass, energy, and momentum conservation laws incorporating gradient corrections.
• Showcased particle-hole symmetry's role in semiclassical simulations.
• Distinguished between Pauli-blocked and Bose-stimulated collisions, with the latter appearing only with gradient corrections.
• Demonstrated the effect of collision delay on shear viscosity in normal-state ultracold Fermi gases.

Conclusions:

• Gradient corrections and collision dynamics significantly influence conservation laws in ultracold Fermi gases.
• Collision delay is a key factor affecting transport properties such as shear viscosity.
• The generalized Boltzmann equation provides a robust framework for studying these systems.