Viscous Properties of a Degenerate One-Dimensional Fermi Gas

Area of Science:

• Condensed Matter Physics
• Quantum Fluids
• Low-Dimensional Systems

Background:

• Understanding the quantum mechanical behavior of interacting fermions is crucial.
• Viscous properties of one-dimensional systems present unique challenges.
• Spin-1/2 fermions exhibit complex dynamics under interaction.

Purpose of the Study:

• To determine the bulk viscosity of a weakly interacting spin-1/2 fermion system in one dimension.
• To analyze the transition to two-fluid hydrodynamics at higher frequencies.
• To calculate transport coefficients in the two-fluid regime.

Main Methods:

• Calculating quasiparticle energy spectrum with interactions.
• Deriving bulk viscosity for low temperatures and low frequencies.
• Analyzing excitation decoupling from center-of-mass motion.
• Applying two-fluid hydrodynamics for higher frequencies.

Main Results:

• Obtained the bulk viscosity for low temperatures and frequencies below the fermion backscattering rate.
• Identified the transition to two-fluid hydrodynamics for frequencies exceeding the backscattering rate.
• Calculated three key transport coefficients for viscous dissipation in the two-fluid regime.

Conclusions:

• The viscous properties of spin-1/2 fermions are strongly influenced by interactions.
• Two-fluid hydrodynamics accurately describes the system at higher frequencies.
• The study provides a comprehensive framework for understanding quantum fluid dissipation.