Superfluid transition in a rotating fermi gas with resonant interactions

Area of Science:

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

Background:

• Superfluidity in atomic Fermi gases is crucial for understanding quantum many-body phenomena.
• Feshbach resonances enable tuning of interactions, facilitating studies across the BEC-BCS crossover.
• Rotation introduces vortices and affects superfluid properties, particularly the critical velocity.

Purpose of the Study:

• To predict the upper-critical angular velocity (ωc2) for a rotating atomic Fermi gas in a uniaxial trap.
• To analyze how ωc2 varies with temperature (T) and detuning (δ) across the BEC-BCS crossover.
• To distinguish the mechanisms suppressing superfluidity in the BCS and BEC regimes.

Main Methods:

• Theoretical analysis of a rotating atomic Fermi gas near an s-wave Feshbach resonance.
• Modeling within a uniaxial trap with specific trap frequencies (Ω⊥, Ωz).
• Calculation of ωc2 as a function of temperature and detuning across the BEC-BCS crossover.

Main Results:

• The upper-critical angular velocity (ωc2) is predicted as a function of temperature and detuning.
• In the BCS and crossover regimes (0 ≤ δ ≤ δc), ωc2 is suppressed and vanishes near resonance.
• In the BEC regime (δ < 0), ωc2 approaches Ω⊥, with superfluidity destroyed by quantum fluctuations.

Conclusions:

• Superfluidity suppression mechanisms differ significantly between the BCS (depairing) and BEC (molecular dilution, quantum fluctuations) regimes.
• The predicted ωc2 provides a benchmark for experimental studies of rotating ultracold Fermi gases.
• The study extends theoretical understanding of rotational effects on superfluidity in tunable quantum gases.