Finite temperature vortices in a rotating Fermi gas

Abstract

Vortices and vortex arrays have been used as a hallmark of superfluidity in rotated, ultracold Fermi gases. These superfluids can be described in terms of an effective field theory for a macroscopic wave function representing the field of condensed pairs, analogous to the Ginzburg-Landau theory for superconductors. Here, we have established how rotation modifies this effective field theory, by rederiving it starting from the action of Fermi gas in the rotating frame of reference. The rotation leads to the appearance of an effective vector potential, and the coupling strength of this vector potential to the macroscopic wave function depends on the interaction strength between the fermions, due to a renormalization of the pair effective mass in the effective field theory. The mass renormalization derived here is in agreement with results of functional renormalization group theory. In the extreme BEC regime, the pair effective mass tends to twice the fermion mass, in agreement with the physical picture of a weakly interacting Bose gas of molecular pairs. Then, we use our macroscopic wave function description to study vortices and the critical rotation frequencies to form them. Equilibrium vortex state diagrams are derived, and they are in good agreement with available results of the Bogoliubov - De Gennes theory and with experimental data.

32 pages, 6 figures, accepted in Phys. Rev. A (2016)

References in corpus (17)

• Many-Body Physics with Ultracold Gases
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• Quantum Fluctuations in the Superfluid State of the BCS-BEC Crossover
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• Pair-Breaking in Rotating Fermi Gases
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• Destroying superfluidity by rotating a Fermi gas at unitarity
• Vortex line in a neutral finite-temperature superfluid Fermi gas
• Superfluid transition in a rotating resonantly-interacting Fermi gas
• Quantum phase transitions and Berezinskii-Kosterlitz-Thouless temperature in a two-dimensional spin-orbit-coupled Fermi gas
• Vortex formation in a rotating two-component Fermi gas
• Pair density waves and vortices in an elongated two-component Fermi gas
• Vortex Properties of a Resonant Superfluid
• Extension of the Ginzburg - Landau approach for ultracold Fermi gases below a critical temperature

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• Diversified vortex phase diagram for a rotating trapped two-band Fermi gas in the BCS-BEC crossover
• Dark soliton collisions in superfluid Fermi gases
• Crossover between snake instability and Josephson instability of dark solitons in superfluid Fermi gases
• Universal description of massive point vortices and verification methods of vortex inertia in superfluids
• Vortices in Fermi gases with spin-dependent rotation potentials
• Vortex Mass in Superfluid Fermi Gases along the BEC-BCS Crossover