Disorderless localization of polar gases in one-dimensional lattice

One-dimensional polar gases in deep optical lattices present a severely constrained dynamics due to the interplay between dipolar interactions, energy conservation, and finite bandwidth. The appearance of dynamically-bound nearest-neighbor dimers results, due to the surprisingly relevant role of the $1/r^3$ tail of the dipolar interactions, in localization via dimer clusterization for very low densities, even for moderate dipole strengths. Furthermore, even weak dipoles, allow for self-bound superfluid or metallic lattice droplets with a finite doping of mobile, but confined, holons. Our results, which can be extrapolated to other power-law interactions, are directly relevant for current and future lattice experiments with magnetic atoms and polar molecules.