Exact study of the one-dimensional boson Hubbard model with a superlattice potential
|Title||Exact study of the one-dimensional boson Hubbard model with a superlattice potential|
|Publication Type||Journal Article|
|Year of Publication||2006|
|Authors||Rousseau, V. G., Arovas D. P., Rigol M., Hebert F., Batrouni G. G., and Scalettar R. T.|
|Journal||Physical Review B|
We use quantum Monte Carlo simulations and exact diagonalization to explore the phase diagram of the Bose-Hubbard model with an additional superlattice potential. We first analyze the properties of superfluid and insulating phases present in the hard-core limit where an exact analytic treatment is possible via the Jordan-Wigner transformation. The extension to finite on-site interactions is achieved by means of quantum Monte Carlo simulations. We determine insulator and superfluid phase diagrams as functions of the on-site repulsive interaction, superlattice potential strength, and filling, finding that insulators with fractional occupation numbers, which are present in the hard-core case, extend deep into the soft-core region. Furthermore, at integer fillings, we find that the competition between the on-site repulsion and the superlattice potential can produce a phase transition between a Mott insulator and a charge-density-wave insulator, with an intermediate superfluid phase. Our results are relevant to the behavior of ultracold atoms in optical superlattices which are beginning to be studied experimentally.