Kosterlitz-Thouless transition and vortex-antivortex lattice melting in two-dimensional Fermi gases with $p$- or $d$-wave pairing

Abstract

We present a theoretical study of the finite-temperature Kosterlitz-Thouless (KT) and vortex-antivortex lattice (VAL) melting transitions in two-dimensional Fermi gases with $p$- or $d$-wave pairing. For both pairings, when the interaction is tuned from weak to strong attractions, we observe a quantum phase transition from the Bardeen-Cooper-Schrieffer (BCS) superfluidity to the Bose-Einstein condensation (BEC) of difermions. The KT and VAL transition temperatures increase during this BCS-BEC transition and approach constant values in the deep BEC region. The BCS-BEC transition is characterized by the non-analyticities of the chemical potential, the superfluid order parameter, and the sound velocities as functions of the interaction strength at both zero and finite temperatures; however, the temperature effect tends to weaken the non-analyticities comparing to the zero temperature case. The effect of mismatched Fermi surfaces on the $d$-wave pairing is also studied.

References in corpus (20)

• Theory of ultracold Fermi gases
• Vortices and Superfluidity in a Strongly Interacting Fermi Gas
• Degenerate Quantum Gases with Spin-Orbit Coupling
• Resonantly-paired fermionic superfluids
• Radiofrequency spectroscopy of a strongly interacting two-dimensional Fermi gas
• Quantum Fluctuations in the Superfluid State of the BCS-BEC Crossover
• Equation of state of a superfluid Fermi gas in the BCS-BEC crossover
• Observation of the Berezinskii-Kosterlitz-Thouless Phase Transition in an Ultracold Fermi Gas
• Observation of pair condensation in the quasi-2D BEC-BCS crossover
• Anisotropic Fermi Superfluid via p-wave Feshbach Resonance
• Spin-Imbalanced Quasi-Two-Dimensional Fermi Gases
• Berezinskii-Kosterlitz-Thouless transition in trapped quasi-two-dimensional Fermi gas near a Feshbach resonance
• The effect of population imbalance on the Berezinskii-Kosterlitz-Thouless phase transition in a superfluid Fermi gas
• Effects of spin-orbit coupling on the Berezinskii-Kosterlitz-Thouless transition and the vortex-antivortex structure in two-dimensional Fermi gases
• Berezinskii-Kosterlitz-Thouless Phase Transition in 2D Spin-Orbit Coupled Fulde-Ferrell Superfluids
• Pseudogap and preformed pairs in the imbalanced Fermi gas in two dimensions
• Observation of broad p-wave Feshbach resonances in ultracold ${}^{85}$Rb-${}^{87}$Rb mixtures
• Nonzero orbital angular momentum superfluidity in ultracold Fermi gases
• Superfluid density and Berezinskii-Kosterlitz-Thouless transition of a spin-orbit coupled Fulde-Ferrell superfluid
• BCS-BEC quantum phase transition and collective excitations in two-dimensional Fermi gases with p- and d-wave pairings