Superfluid <i>vs.</i> Mott-Insulator Phase in Imperfect Multi-Rods Lattices

We calculate the ground state (GS) energy and the static structure factor at zero temperature of an interacting Bose gas confined by a one-dimensional, periodic, multi-rods lattice created by an external Kronig-Penney potential. We employ the Diffusion Monte Carlo (DMC) method to estimate the physical properties exactly up to a statistical error. In the limit of zero external potential, we recover the results for the well-known Lieb-Liniger model. Using the Luttinger Liquid formalism for the low-energy properties of 1D systems, we find a phase transition from the superfluid state to the Mott insulator state as the lattice height increases. Also, we report that the introduction of a barrier defect in the lattice favors the superfluid phase with respect to the Mott insulator phase.