Quantum Monte Carlo Study of a Dynamic Hubbard Model

Abstract

The `dynamic' Hubbard Hamiltonian describes interacting fermions on a lattice whose on-site repulsion is modulated by a coupling to a fluctuating bosonic field. We investigate one such model, introduced by Hirsch, using the determinant Quantum Monte Carlo method. Our key result is that the extended s-wave pairing vertex, repulsive in the usual static Hubbard model, becomes attractive as the coupling to the fluctuating Bose field increases. The sign problem prevents us from exploring a low enough temperature to see if a superconducting transition occurs. We also observe a stabilization of antiferromagnetic correlations and the Mott gap near half-filling, and a near linear behavior of the energy as a function of particle density which indicates a tendency toward phase separation.

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Cited by in corpus (5)

• Charge expulsion, charge inhomogeneity and phase separation in dynamic Hubbard models
• Surprises in the t-J model: Implications for cuprates
• Two-site dynamical mean field theory for the dynamic Hubbard model
• Dynamic Hubbard model for solids with hydrogen-like atoms
• Analytical Continuation Approaches to Electronic Transport: The Resonant Level Model