Observation of confinement-induced resonances in a 3D lattice

We report on the observation of confinement-induced resonances (CIRs) for strong zero-dimensional (0D) confinement in a three-dimensional (3D) optical lattice potential. Starting from a Mott-insulator state with mainly single-site occupancy, we detect loss and heating features at specific values for the confinement length scale and the 3D scattering length, in isotropic and anisotropic lattice potentials. Two independent models, describing the coupling between the center-of-mass and the relative motion of the particles as mediated by the lattice, predict the resonance positions to a good approximation, suggesting a universal behavior. Our results show that CIRs exist for any dimensionality and open up a new method for interaction tuning and controlled molecule formation under strong 0D confinement.