Quantum phase transitions in the Fermi-Bose Hubbard model
Abstract
We propose a multi-band Fermi-Bose Hubbard model with on-site fermion-boson conversion and general filling factor in three dimensions. Such a Hamiltonian models an atomic Fermi gas trapped in a lattice potential and subject to a Feshbach resonance. We solve this model in the two state approximation for paired fermions at zero temperature. The problem then maps onto a coupled Heisenberg spin model. In the limit of large positive and negative detuning, the quantum phase transitions in the Bose Hubbard and Paired-Fermi Hubbard models are correctly reproduced. Near resonance, the Mott states are given by a superposition of the paired-fermion and boson fields and the Mott-superfluid borders go through an avoided crossing in the phase diagram.
Cite
@article{arxiv.cond-mat/0501156,
title = {Quantum phase transitions in the Fermi-Bose Hubbard model},
author = {L. D. Carr and M. J. Holland},
journal= {arXiv preprint arXiv:cond-mat/0501156},
year = {2009}
}
Comments
4 pages, 3 figures