Superfluidity, Sound Velocity and Quasi Condensation in the 2D BCS-BEC Crossover

Abstract

We study finite-temperature properties of a two-dimensional superfluid made of ultracold alkali-metal atoms in the BCS-BEC crossover. We investigate the region below the critical temperature $T_{BKT}$ of the Berezinskii-Kosterlitz-Thouless phase transition, where there is quasi-condensation, by analyzing the effects of phase and amplitude fluctuations of the order parameter. In particular, we calculate the superfluid fraction, the sound velocity and the quasi-condensate fraction as a function of the temperature and of the binding energy of fermionic pairs.

7 pages, 4 figures, improved version to be published in Phys. Rev. A

References in corpus (9)

• Observation of Bose-Einstein Condensation of Molecules
• Observation of the Pairing Gap in a Strongly Interacting Fermi Gas
• Phase diagram of a two-component Fermi gas with resonant interactions
• Pairing fluctuations and the superfluid density through the BCS-BEC crossover
• The effect of population imbalance on the Berezinskii-Kosterlitz-Thouless phase transition in a superfluid Fermi gas
• Pseudogap and preformed pairs in the imbalanced Fermi gas in two dimensions
• Condensate Fraction of a Two-Dimensional Attractive Fermi Gas
• Condensate formation with three-component ultracold fermions
• Pair condensation in the BCS-BEC crossover of ultracold atoms loaded onto a 2D square lattice

Cited by in corpus (25)

• Quantum fluctuations in the BCS-BEC crossover of two-dimensional Fermi gases
• Finite-temperature quantum fluctuations in two-dimensional Fermi superfluids
• Finite temperature effective field theory and two-band superfluidity in Fermi gases
• Superfluid density and critical velocity near the fermionic Berezinskii-Kosterlitz-Thouless transition
• Composite bosons in the 2D BCS-BEC crossover from Gaussian fluctuations
• Vortices and antivortices in two-dimensional ultracold Fermi gases
• Quasi-condensation in two-dimensional Fermi gases
• Superfluid density and Berezinskii-Kosterlitz-Thouless transition of a spin-orbit coupled Fulde-Ferrell superfluid
• Dimensional crossover in a strongly interacting ultracold atomic Fermi gas
• Stoner ferromagnetism in a thermal pseudospin-1/2 Bose gas
• Effects of quantum fluctuations on the low-energy collective modes of two-dimensional superfluid Fermi gases from the BCS to the Bose Limit
• Gauge invariant theories of linear response for strongly correlated superconductors
• Mobile impurity probing a two-dimensional superfluid phase transition
• Pseudogap phenomena in a two-dimensional ultracold Fermi gas near the Berezinskii-Kosterlitz-Thouless transition
• Renormalization of the superfluid density in the two-dimensional BCS-BEC crossover
• Josephson effect as signature of electron-hole superfluidity in bilayers of van der Waals heterostructures
• Quantum fluctuations and vortex-antivortex unbinding in the 2D BCS-BEC crossover
• Kosterlitz-Thouless transition and vortex-antivortex lattice melting in two-dimensional Fermi gases with $p$- or $d$-wave pairing
• Strong pairing in two dimensions: Pseudogaps, domes, and other implications
• Goldstone and Higgs Hydrodynamics in the BCS-BEC Crossover
• Gaussian fluctuations in the two-dimensional BCS-BEC crossover: finite temperature properties
• Predictive power of the Berezinskii-Kosterlitz-Thouless theory based on Renormalization Group throughout the BCS-BEC crossover in 2D superconductors
• Pair condensation of polarized fermions in the BCS-BEC crossover
• Effect of Weak Disorder on the BCS-BEC crossover in a two-dimensional Fermi Gas
• Phase correlations and quasicondensate in a two-dimensional ultracold Fermi gas