Superfluid transition in a rotating resonantly-interacting Fermi gas

Abstract

We study a rotating atomic Fermi gas near a narrow s-wave Feshbach resonance in a uniaxial harmonic trap with frequencies ${\Omega }_{\perp }$, ${\Omega }_z$. Our primary prediction is the upper-critical angular velocity, ${\omega }_{c2}(\delta ,T)$, as a function of temperature $T$ and resonance detuning $\delta$, ranging across the BEC-BCS crossover. The rotation-driven suppression of superfluidity at ${\omega }_{c2}$ is quite distinct in the BCS and BEC regimes, with the former controlled by Cooper-pair depairing and the latter by the dilution of bosonic molecules. At low $T$ and ${\Omega }_z\ll {\Omega }_{\perp }$, in the BCS and crossover regimes of $0\lesssim \delta \lesssim {\delta }_c$, ${\omega }_{c2}$ is implicitly given by $\hslash \sqrt{{\omega }_{c2}^2+{\Omega }_{\perp }^2}\approx 2\Delta \sqrt{\hslash {\Omega }_{\perp }/{\epsilon }_F}$, vanishing as ${\omega }_{c2}\sim {\Omega }_{\perp }(1-\delta /{\delta }_c{)}^{1/2}$ near ${\delta }_c\approx 2{\epsilon }_F+\frac{\gamma }{2}{\epsilon }_F\ln ({\epsilon }_F/\hslash {\Omega }_{\perp })$ (with $\Delta$ the BCS gap and $\gamma$ resonance width), and extending bulk result $\hslash {\omega }_{c2}\approx 2{\Delta }^2/{\epsilon }_F$ to a finite number of atoms in a trap. In the BEC regime of $\delta <0$ we find ${\omega }_{c2}\to {\Omega }_{\perp }^{-}$, where molecular superfluidity can only be destroyed by large quantum fluctuations associated with comparable boson and vortex densities.

4 pages, 3 figures

References in corpus (2)

• Vortices and Superfluidity in a Strongly Interacting Fermi Gas
• Nonequilibrium dynamics and thermodynamics of a degenerate Fermi gas across a Feshbach resonance

Cited by in corpus (4)

• Theory of ultracold Fermi gases
• Superfluid Expansion of a Strongly Interacting Fermi Gas
• Density waves and supersolidity in rapidly rotating atomic Fermi gases
• Breathing mode frequencies of a rotating Fermi gas in the BCS-BEC crossover region