Synthetic gauge fields and Landau levels in acoustic Moiré superlattices

The synthetic gauge field, offering an excellent platform to explore some fascinating magnetic-like phenomena, has attracted extensive research. Here, we report the realization of a synthetic gauge field in acoustic Moiré superlattices consisting of two superimposed periodic phononic crystals with mismatched lattice constants along one direction. Benefiting from the synthetic gauge field, we observe the symmetric and antisymmetric Landau levels and interface states in the acoustic Moiré superlattices. We further experimentally measure sound pressure field distributions of Landau levels, which is consistent with the full-wave simulations. This study offers an extremely simple way to generate synthetic gauge fields in phononics and expand the avenues for manipulating sound waves that were previously inaccessible in traditional periodic acoustic systems.