Incommensurability Effects on Dipolar Bosons in Optical Lattices

We present a study that investigated a quantum dipolar gas in continuous space where a potential lattice was imposed. Employing exact quantum Monte Carlo techniques, we analysed the ground-state properties of the scrutinised system, varying the lattice depth and the dipolar interaction. For system densities corresponding to a commensurate filling with respect to the optical lattice, we observed a simple crystal- to-superfluid quantum phase transition, being consistent with the physics of dipolar bosons in continuous space. In contrast, an incommensurate density showed the pres- ence of a supersolid phase. Indeed, such a result opens up the tempting opportunity to observe a defect-induced supersolidity with dipolar gases in combination with a tunable optical lattice. Finally, the stability of the condensate was analysed at finite temperature.