Mean-field theory for the Mott-insulator–paired-superfluid phase transition in the two-species Bose-Hubbard model

Abstract

The standard mean-field theory for the Mott-insulator–superfluid phase transition is not sufficient to describe the Mott-insulator–paired-superfluid phase transition. Therefore, by restricting the two-species Bose-Hubbard Hamiltonian to the subspace of paired particles, and using perturbation theory, here we derive an analytic mean-field expression for the Mott-insulator–paired-superfluid transition boundary.