Mott-insulator phases of nonlocally coupled one-dimensional dipolar Bose gases

We analyze the Mott-insulator phases of dipolar bosonic gases placed in neighboring but unconnected one-dimensional (1D) traps. Whereas for short-range interactions the 1D systems are independent, the non-local dipole-dipole interaction induces a direct Mott-insulator to pair-superfluid transition which significantly modifies the boundaries of the lowest Mott-insulator phases. The lowest boundary of the lowest Mott regions becomes progressively constant as a function of the hopping rate, eventually inverting its slope, leading to a reentrant configuration which is retained in two dimensions. We discuss the consequences of this effect on the spatial Mott-insulator plateaux in experiments with additional harmonic confinement, showing that counterintuitively the plateaux may become wider for increasing hopping. Our results are also applicable to nondipolar boson-boson mixtures.