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.
Cite
@article{arxiv.0710.1356,
title = {Quantum Monte Carlo Study of a Dynamic Hubbard Model},
author = {K. Bouadim and M. Enjalran and F. Hebert and G. G. Batrouni and R. T. Scalettar},
journal= {arXiv preprint arXiv:0710.1356},
year = {2009}
}