A real space auxiliary field approach to the BCS-BEC crossover

Abstract

The BCS to BEC crossover in attractive Fermi systems is a prototype of weak to strong coupling evolution in many body physics. While extensive numerical results are available, and several approximate methods have been developed, most of these schemes are unsuccessful in the presence of spatial inhomogeneity. Such situations call for a real space approach that can handle large spatial scales and retain the crucial thermal fluctuations. With this in mind, we present comprehensive results of a real space auxiliary field approach to the BCS to BEC crossover in the attractive Hubbard model in two dimensions. The scheme reproduces the Hartree-Fock-Bogoliubov ground state, and leads to a $T_c$ scale that agrees with quantum Monte Carlo estimates to within a few percent. We provide results on the $T_c$, amplitude and phase fluctuations, density of states, and the momentum resolved spectral function over the entire interaction and temperature window. We suggest how the method generalises successfully to the presence of disorder, trapping, and population imbalance.

This article supersedes arXiv:1105.1156

References in corpus (7)

• Theory of ultracold Fermi gases
• Nature of the superconductor-insulator transition in disordered superconductors
• Dynamical mean-field theory and numerical renormalization group study of superconductivity in the attractive Hubbard model
• Berezinskii-Kosterlitz-Thouless transition and BCS-Bose crossover in the two-dimensional attractive Hubbard model
• Quasiparticle excitations and dynamic susceptibilities in the BCS-BEC crossover
• Charge Dynamics Across the Disorder Driven Superconductor-Insulator Transition
• Radio frequency spectroscopy of the attractive Hubbard model in a trap

Cited by in corpus (14)

• Non Fermi liquid behavior and continuously tunable resistivity exponents in the Anderson-Hubbard model at finite temperature
• Parallelized Traveling Cluster Approximation to Study Numerically Spin-Fermion Models on Large Lattices
• Strain induced superconductor-insulator transition on Lieb lattice
• Strong coupling s-wave superconductors in the extreme Pauli limit: I.The breached pair and metastable FFLO phases
• Population imbalanced lattice fermions near the BCS-BEC crossover: I.The breached pair and metastable FFLO phases
• Population imbalanced lattice fermions near the BCS-BEC crossover: II. The FFLO regime and its thermal signatures
• Nonequilibrium dynamics of superconductivity in the attractive Hubbard model
• Orbital Selective Directional Conductor in the Two Orbital Hubbard Model
• Pauli limited d-wave superconductors: Quantum breached pair phase and thermal transitions
• The impact of speckle disorder on a superfluid Fermi system
• Effective Hamiltonian based Monte Carlo for the BCS to BEC crossover in the attractive Hubbard model
• Effect of site dilution in the two-dimensional attractive Hubbard model
• Anomalous pseudogap in population imbalanced Fermi superfluids
• Transport and spectroscopic signatures of a disorder-stabilized metal in two-dimensional frustrated Mott insulators