Super-ballistic diffusion induced by nonlinear interactions in a one-dimensional quasiperiodic lattice

We numerically investigate the spreading dynamics of wave packets in a one-dimensional lattice with quasiperiodic disorders and nonlinear interactions. Under moderate disorder strength, we reveal an intriguing super-ballistic diffusion driven by increasing the interaction strength from the ballistic diffusion in the non- and weakly interacting cases. We obtain a wide parameter region for such a faster-than-ballistic spreading of wave packets in the quasiperiodic lattice, although the nonlinear self-trapping is dominated under strong interactions. The super-ballistic diffusion is further analyzed based on the point source model. We also show the interaction-induced sub-diffusive spreading in the Anderson localized regime. The super-ballistic and sub-diffusive dynamics are exhibited in the spreading that starts from both the single-site and Gaussian wave packets. Our results showcase the interaction-enabled super-ballistic diffusion, which is scarce and experimentally realizable in artificial atomic or photonic lattices. •The super-ballistic diffusion induced by nonlinear interactions in a one-dimensional quasiperiodic lattice is revealed, which indicates the faster-than-ballistic spreading of wave packets.•A point source model is implemented to analyze the dynamic exponent and the physical picture of the super-ballistic diffusion.•The super-ballistic diffusion can be exhibited for single-site and Gaussian wave packets, which could be experimentally observed in artificial atomic or photonic lattices.