Realization of a Non-Quantized Square-Root Topological Insulator Based on Photonic Aharonov-Bohm Cages

摘要

We report a new type of insulator that exhibits spectral bands with non-quantized topological properties. Furthermore, a quantisation manifests itself upon squaring the Hamiltonian. We experimentally verify our claims by using photonic Aharonov-Bohm cages.