FFLO correlation and free fluids in the one-dimensional attractive Hubbard model

Abstract

In this Rapid Communication we show that low energy macroscopic properties of the one-dimensional (1D) attractive Hubbard model exhibit two fluids of bound pairs and of unpaired fermions. Using the thermodynamic Bethe ansatz equations of the model, we first determine the low temperature phase diagram and analytically calculate the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) pairing correlation function for the partially-polarized phase. We then show that for such a FFLO-like state in the low density regime the effective chemical potentials of bound pairs and unpaired fermions behave like two free fluids. Consequently, the susceptibility, compressibility and specific heat obey simple additivity rules, indicating the `free' particle nature of interacting fermions on a 1D lattice. In contrast to the continuum Fermi gases, the correlation critical exponents and thermodynamics of the attractive Hubbard model essentially depend on two lattice interacting parameters. Finally, we study scaling functions, the Wilson ratio and susceptibility which provide universal macroscopic properties/dimensionless constants of interacting fermions at low energy.

In this Letter we analytically study FFLO pairing correlation and the universal nature of the FFLO-like state. More detailed studies of this model will be presented in arXiv:1710.08742 and arXiv:1708.07784

References in corpus (8)

• Observation of antiferromagnetic correlations in the Hubbard model with ultracold atoms
• Phase diagram of a strongly interacting polarized Fermi gas in one dimension
• Two-dimensional Mott-Hubbard electrons in an artificial honeycomb lattice
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• Phase Transitions and Pairing Signature in Strongly Attractive Fermi Atomic Gases
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Cited by in corpus (7)

• Grüneisen Parameters: origin, identity and quantum refrigeration
• Enhanced visibility of the Fulde-Ferrell-Larkin-Ovchinnikov state in one dimensional Bose-Fermi mixtures near the immiscibility point
• Signatures of the BCS-BEC crossover in the yrast spectra of Fermi quantum rings
• Quantum critical behavior and thermodynamics of the repulsive one-dimensional Hubbard model in a magnetic field
• Fulde-Ferrell-Larkin-Ovchinnikov pairing states of a polarized dipolar Fermi gas trapped in a one-dimensional optical lattice
• Spin incoherent liquid and interaction-driven criticality in 1D Hubbard model
• Unconventional pairing in few-fermion systems tuned by external confinement