The effect of population imbalance on the Berezinskii-Kosterlitz-Thouless phase transition in a superfluid Fermi gas

Abstract

The Berezinskii-Kosterlitz-Thouless (BKT) mechanism describes the breakdown of superfluidity in a two-dimensional Bose gas or a two-dimensional gas of paired fermions. In the latter case, a population imbalance between the two pairing partners in the Fermi mixture is known to influence pairing characteristics. Here, we investigate the effects of imbalance on the two-dimensional BKT superfluid transition, and show that superfluidity is even more sensitive to imbalance than for three dimensional systems. Finite-temperature phase diagrams are derived using the functional integral formalism in combination with a hydrodynamic action functional for the phase fluctuations. This allow to identify a phase separation region and tricritical points due to imbalance. In contrast to superfluidity in the three-dimensional case, the effect of imbalance is also pronounced in the strong-coupling regime.

3 figures

References in corpus (16)

• Many-Body Physics with Ultracold Gases
• Quantum phase transition from a superfluid to a Mott insulator in a gas of ultracold atoms
• Evidence for Superfluidity of Ultracold Fermions in an Optical Lattice
• Direct Observation of the Superfluid Phase Transition in Ultracold Fermi Gases
• Phase diagram of a two-component Fermi gas with resonant interactions
• Interference of an array of independent Bose-Einstein condensates
• Critical Point of an Interacting Two-Dimensional Atomic Bose Gas
• The trapped two-dimensional Bose gas: from Bose-Einstein condensation to Berezinskii-Kosterlitz-Thouless physics
• Pairing fluctuations and the superfluid density through the BCS-BEC crossover
• Kosterlitz-Thouless transition of the quasi two-dimensional trapped Bose gas
• Berezinskii-Kosterlitz-Thouless transition in trapped quasi-two-dimensional Fermi gas near a Feshbach resonance
• Isospin Dependence in the Odd-Even Staggering of Nuclear Binding Energies
• Competing orders in thermally fluctuating superconductors in two dimensions
• Superfluidity of an interacting trapped quasi-2D Bose gas
• Imbalanced Fermi superfluid in a one-dimensional optical potential
• Imbalanced d-wave superfluids in the BCS-BEC crossover regime at finite temperatures

Cited by in corpus (14)

• Crossover from 2D to 3D in a weakly interacting Fermi gas
• Spin-Imbalanced Quasi-Two-Dimensional Fermi Gases
• Exact few-body results for strongly correlated quantum gases in two dimensions
• Effects of spin-orbit coupling on the Berezinskii-Kosterlitz-Thouless transition and the vortex-antivortex structure in two-dimensional Fermi gases
• Pseudogap and preformed pairs in the imbalanced Fermi gas in two dimensions
• Polaron Problems in Ultracold Atoms: Role of a Fermi Sea across Different Spatial Dimensions and Quantum Fluctuations of a Bose Medium
• Composite bosons in the 2D BCS-BEC crossover from Gaussian fluctuations
• BCS-BEC crossover of atomic Fermi superfluid in a spherical bubble trap
• Pseudogap phenomena in a two-dimensional ultracold Fermi gas near the Berezinskii-Kosterlitz-Thouless transition
• Kosterlitz-Thouless transition and vortex-antivortex lattice melting in two-dimensional Fermi gases with $p$- or $d$-wave pairing
• Pseudogap regime of a two-dimensional uniform Fermi gas
• Vortex Mass in Superfluid Fermi Gases along the BEC-BCS Crossover
• Phase correlations and quasicondensate in a two-dimensional ultracold Fermi gas
• Effect of Population Imbalance on Vortex Mass in Superfluid Fermi Gases