Acoustic realization of projective mirror Chern insulators

Symmetry plays a key role in classifying topological phases. Recent theory shows that in the presence of gauge fields, the algebraic structure of crystalline symmetries needs to be projectively represented, which brings extra chance for topological physics. Here, we report a concrete acoustic realization of mirror Chern insulators by exploiting the concept of projective symmetry. Specifically, we introduce a simple but universal recipe for constructing projective mirror symmetry, and conceive a minimal model for achieving the projective symmetry-enriched mirror Chern insulators. Based on our selective-excitation measurements, we demonstrate unambiguously the projective mirror eigenvalue-locked topological nature of the bulk states and associated chiral edge states. We extract the non-abelian Berry curvature and identify the mirror Chern number directly, providing experimental evidence for this exotic topological phase. All experimental results agree well with the theoretical predictions. Our findings give insights into topological systems equipped with gauge fields. A recurring theme in physics has been the discovery of distinctive phases of matter. Here, the authors propose a general recipe for constructing projective mirror symmetry and report an experimental realization of mirror Chern insulators in spinless systems.

Automated summary

Symmetry plays a key role in classifying topological phases. Recent theory shows that in the presence of gauge fields, the algebraic structure of crystalline symmetries needs to be projectively represented. This study reports the experimental realization of mirror Chern insulators in acoustic systems by exploiting the concept of projective symmetry.