Superfluidity and pairing phenomena in ultracold atomic Fermi gases in one-dimensional optical lattices, Part II: Effects of population imbalance

Abstract

In this paper, we study the effect of population imbalance and its interplay with pairing strength and lattice effect in atomic Fermi gases in a one-dimensional optical lattice. We compute various phase diagrams as the system undergoes BCS-BEC crossover, using the same pairing fluctuation theory as in Part I. We find widespread pseudogap phenomena beyond the BCS regime and intermediate temperature superfluid states for relatively low population imbalances. The Fermi surface topology plays an important role in the behavior of $T_{\text{c}}$. For large $d$ and/or small $t$, which yield an open Fermi surface, superfluidity can be readily destroyed by a small amount of population imbalance $p$. The superfluid phase, especially in the BEC regime, can exist only for a highly restricted volume of the parameter space. Due to the continuum-lattice mixing, population imbalance gives rise to a new mechanism for pair hopping, as assisted by excessive majority fermions, which may lead to significant enhancement of $T_{\text{c}}$ on the BEC side of the Feshbach resonance, and also render $T_{\text{c}}$ approaching a constant asymptote in the BEC limit, when it exists. Furthermore, we find that not all minority fermions will be paired up in BEC limit, unlike the 3D continuum case. These predictions can be tested in future experiments.

arXiv comment14 pages, 14 figures in color

References in corpus (41)

• Many-Body Physics with Ultracold Gases
• Theory of ultracold Fermi gases
• Bose-Einstein condensation of atoms in a uniform potential
• BCS-BEC Crossover: From High Temperature Superconductors to Ultracold Superfluids
• Homogeneous Atomic Fermi Gases
• Observation of a pairing pseudogap in a two-dimensional Fermi gas
• Pairing Fluctuation Theory of Superconducting Properties in Underdoped to Overdoped Cuprates
• Evolution of Fermion Pairing from Three to Two Dimensions
• Pairing states of a polarized Fermi gas trapped in a one-dimensional optical lattice
• Two-Dimensional Homogeneous Fermi Gases
• Superfluid stability in BEC-BCS crossover
• Crossover from 2D to 3D in a weakly interacting Fermi gas
• Fulde-Ferrell-Larkin-Ovchinnikov superfluidity in one-dimensional optical lattices
• Thermodynamics of $n$-$p$ condensate in asymmetric nuclear matter
• Highly polarized Fermi gases in two dimensions
• Spin-Imbalanced Quasi-Two-Dimensional Fermi Gases
• Intermediate temperature superfluidity in an atomic Fermi gas with population imbalance
• Superfluidity at the BEC-BCS crossover in two-dimensional Fermi gases with population and mass imbalance
• Pseudogaps in strongly interacting Fermi gases
• Spectral signatures of the Fulde-Ferrell-Larkin-Ovchinnikov order parameter in one-dimensional optical lattices
• Phase separation and pair condensation in a spin-imbalanced 2D Fermi gas
• Phase Diagram of Cold Polarized Fermi Gas in Two Dimensions
• Thermodynamics and superfluid density in BCS-BEC crossover with and without population imbalance
• Finite Temperature Phase Diagram of a Two-Component Fermi Gas with Density Imbalance
• Stability conditions and phase diagrams for two component Fermi gases with population imbalance
• Enhancement effect of mass imbalance on Fulde-Ferrell-Larkin-Ovchinnikov type of pairing in Fermi-Fermi mixtures of ultracold quantum gases
• Pseudogap and preformed pairs in the imbalanced Fermi gas in two dimensions
• Single-plane-wave Larkin-Ovchinnikov-Fulde-Ferrell state in BCS--Bose-Einstein condensation crossover
• Pseudogap phenomena in ultracold atomic Fermi gases
• Fulde-Ferrell-Larkin-Ovchinnikov critical polarization in one-dimensional fermionic optical lattices
• Instability of Fulde-Ferrell-Larkin-Ovchinnikov states in three and two dimensions
• Fulde-Ferrell-Larkin-Ovchinnikov state of two-dimensional imbalanced Fermi gases
• The ground state of a mixture of two species of fermionic atoms in 1D optical lattice
• Comment on "Superfluid stability in the BEC-BCS crossover"
• Resonant enhancement of the FFLO-state in 3D by a one-dimensional optical potential
• Controlling the pair momentum of the FFLO state in a 3D Fermi gas through a 1D periodic potential
• Larkin-Ovchinnikov superfluidity in a two-dimensional imbalanced atomic Fermi gas
• Pairing, crystallization and string correlations of mass-imbalanced atomic mixtures in one-dimensional optical lattices
• Unusual destruction and enhancement of superfluidity of atomic Fermi gases by population imbalance in a one-dimensional optical lattice
• Exotic superfluidity and pairing phenomena in atomic Fermi gases in mixed dimensions
• Superfluidity and pairing phenomena in ultracold atomic Fermi gases in one-dimensional optical lattices, Part I: Balanced case

Cited by in corpus (3)

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• Ground states of atomic Fermi gases in a two-dimensional optical lattice with and without population imbalance
• Pairing phenomena and superfluidity of atomic Fermi gases in a two-dimensional optical lattice: Unusual effects of lattice-continuum mixing