Population imbalanced lattice fermions near the BCS-BEC crossover: I.The breached pair and metastable FFLO phases

Abstract

We study s-wave superconductivity in the two dimensional attractive Hubbard model in an applied magnetic field, assume the extreme Pauli limit, and examine the role of spatial fluctuations in the coupling regime corresponding to BCS-BEC crossover. We use a decomposition of the interaction in terms of an auxiliary pairing field, retain the static mode, and sample the pairing field via Monte Carlo. The method requires iterative solution of the Bogoliubov-de-Gennes (BdG) equations for amplitude and phase fluctuating configurations of the pairing field. We establish the full thermal phase diagram of this strong coupling problem, revealing $T_c$ scales an order of magnitude below the mean field estimate, highlight the spontaneous inhomogeneity in the field induced magnetization, and discover a strong non monotonicity in the temperature dependence of the low energy density of states. We compare our results to the experimental phase diagram of the imbalanced Fermi gas at unitarity. This paper focuses on the magnetized but homogeneous (breached pair) superconducting state, a companion paper deals with the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) regime.

17 pages, 17 figures. This version and arXiv:1508.05036 are published as a combined text

References in corpus (30)

• Many-Body Physics with Ultracold Gases
• Theory of ultracold Fermi gases
• Observation of the Pairing Gap in a Strongly Interacting Fermi Gas
• Fulde-Ferrell-Larkin-Ovchinnikov State in Heavy Fermion Superconductors
• Observation of Phase Separation in a Strongly-Interacting Imbalanced Fermi Gas
• Nature of the superconductor-insulator transition in disordered superconductors
• Thermodynamics of the BCS-BEC crossover
• Phase diagram of a two-component Fermi gas with resonant interactions
• Observation of pseudogap behavior in a strongly interacting Fermi gas
• Calorimetric Evidence for a Fulde-Ferrell-Larkin-Ovchinnikov Superconducting State in the Layered Organic Superconductor κ$-(BEDT-TTF)$_2$Cu(NCS)$_2$
• Deformation of a Trapped Fermi Gas with Unequal Spin Populations
• Critical Temperature and Thermodynamics of Attractive Fermions at Unitarity
• Pairing without Superfluidity: The Ground State of an Imbalanced Fermi Mixture
• Observation of pair condensation in the quasi-2D BEC-BCS crossover
• Evidence of Andreev bound states as a hallmark of the FFLO phase in $\kappa$-(BEDT-TTF)${}_2$Cu(NCS)${}_2$
• Fulde-Ferrell-Larkin-Ovchinnikov state in a perpendicular field of quasi two-dimensional CeCoIn5
• Exact quantum Monte Carlo study of one dimensional trapped fermions with attractive contact interactions
• Generic Phase Diagram of Fermion Superfluids with Population Imbalance
• Exact Numerical Study of Pair Formation with Imbalanced Fermion Populations
• Finite temperature phase diagram of a polarized Fermi gas in an optical lattice
• Observation of Spin Susceptibility Enhancement in the Possible FFLO State in CeCoIn${}_5$
• Pairing and Superfluid Properties of Dilute Fermion Gases at Unitarity
• Thermodynamics of a Trapped Unitary Fermi Gas
• Superfluidity at the BEC-BCS crossover in two-dimensional Fermi gases with population and mass imbalance
• Upper critical field study in the organic superconductor ${\beta }^{\prime \prime }$-(ET)${}_2$SF${}_5$CH${}_2$CF${}_2$SO${}_3$ : Possibility of Fulde-Ferrell-Larkin-Ovchinnikov state
• Switching of magnetic domains reveals evidence for spatially inhomogeneous superconductivity
• Polarized superfluidity in the attractive Hubbard model with population imbalance
• Field Dependence of the Ground State in the Exotic Superconductor CeCoIn${}_5$: a Nuclear Magnetic Resonance Investigation
• Berezinskii-Kosterlitz-Thouless transition and BCS-Bose crossover in the two-dimensional attractive Hubbard model
• Oscillatory pairing of fermions in spin-split traps

Cited by in corpus (14)

• The Fulde-Ferrell-Larkin-Ovchinnikov state for ultracold fermions in lattice and harmonic potentials: a review
• Non Fermi liquid behavior and continuously tunable resistivity exponents in the Anderson-Hubbard model at finite temperature
• Doping-controlled transition from excitonic insulator to semimetal in Ta${}_2$NiSe${}_5$
• Strain induced superconductor-insulator transition on Lieb lattice
• Mutual information, quantum phase transition, and phase coherence in Kondo systems
• Development of long-range phase coherence on the Kondo lattice
• Thermal transitions, pseudogap behavior and BCS-BEC crossover in Fermi-Fermi mixtures
• Stability of the Fulde-Ferrell-Larkin-Ovchinnikov states in anisotropic systems and critical behavior at thermal $m$-axial Lifshitz points
• Non-collinear order and gapless superconductivity in s-wave magnetic superconductors
• Fulde-Ferrell-Larkin-Ovchinnikov state in strongly correlated d-wave superconductors
• Spin-orbital liquids and insulator-metal transitions on the pyrochlore lattice
• Anomalous pseudogap in population imbalanced Fermi superfluids
• Transport and spectroscopic signatures of a disorder-stabilized metal in two-dimensional frustrated Mott insulators
• Temperature tuned Fermi surface topology and segmentation in non-centrosymmetric superconductors