Exotic superfluidity and pairing phenomena in atomic Fermi gases in mixed dimensions

Abstract

Atomic Fermi gases have been an ideal platform for simulating conventional and engineering exotic physical systems owing to their multiple tunable control parameters. Here we investigate the effects of mixed dimensionality on the superfluid and pairing phenomena of a two-component ultracold atomic Fermi gas with a short-range pairing interaction, while one component is confined on a one-dimensional (1D) optical lattice whereas the other is in a homogeneous 3D continuum. We study the phase diagram and the pseudogap phenomena throughout the entire BCS-BEC crossover, using a pairing fluctuation theory. We find that the effective dimensionality of the non-interacting lattice component can evolve from quasi-3D to quasi-1D, leading to strong Fermi surface mismatch. Upon pairing, the system becomes effectively quasi-two dimensional in the BEC regime. The behavior of $T_c$ bears similarity to that of a regular 3D population imbalanced Fermi gas, but with a more drastic departure from the regular 3D balanced case, featuring both intermediate temperature superfluidity and possible pair density wave ground state. Unlike a simple 1D optical lattice case, $T_c$ in the mixed dimensions has a constant BEC asymptote.

arXiv commentmain article + supplementary information, 6+1 pages, 7+2 color figures

References in corpus (17)

• Many-Body Physics with Ultracold Gases
• BCS-BEC Crossover: From High Temperature Superconductors to Ultracold Superfluids
• Pairing Fluctuation Theory of Superconducting Properties in Underdoped to Overdoped Cuprates
• Superfluid stability in BEC-BCS crossover
• Scattering in Mixed Dimensions with Ultracold Gases
• Universal Fermi gases in mixed dimensions
• Intermediate temperature superfluidity in an atomic Fermi gas with population imbalance
• Stability conditions and phase diagrams for two component Fermi gases with population imbalance
• Phases of a bilayer Fermi gas
• Pseudogap phenomena in ultracold atomic Fermi gases
• Finite-Temperature Behavior of an Inter-species Fermionic Superfluid with Population Imbalance
• Quasi-condensation in two-dimensional Fermi gases
• Cooper pairing and BCS-BEC evolution in mixed-dimensional Fermi gases
• Phase diagrams of Fermi gases in a trap with mass and population imbalances at finite temperature
• Reentrant Superfluidity and Pair Density Wave in Single Component Dipolar Fermi Gases
• BCS-BEC Crossover in Mix-dimensional Fermi Gases
• Two-dimensional spin-imbalanced Fermi gases at non-zero temperature: Phase separation of a non-condensate

Cited by in corpus (6)

• Superfluidity and pairing phenomena in ultracold atomic Fermi gases in one-dimensional optical lattices, Part I: Balanced case
• Pairing phenomena and superfluidity of atomic Fermi gases in a two-dimensional optical lattice: Unusual effects of lattice-continuum mixing
• Superfluidity and pairing phenomena in ultracold atomic Fermi gases in one-dimensional optical lattices, Part II: Effects of population imbalance
• Ultra high temperature superfluidity in ultracold atomic Fermi gases with mixed dimensionality
• Flat band effects on the ground-state BCS-BEC crossover in atomic Fermi gases in a quasi-two-dimensional Lieb lattice
• Weak three-dimensional mediators of two-dimensional triplet pairing