Measuring topological invariants in a polaritonic analog of graphene

Abstract

Topological materials rely on engineering global properties of their bulk energy bands called topo- logical invariants. These invariants, usually defined over the entire Brillouin zone, are related to the existence of protected edge states. However, for an important class of Hamiltonians correspond- ing to 2D lattices with time-reversal and chiral symmetry (e.g. graphene), the existence of edge states is linked to invariants that are not defined over the full 2D Brillouin zone, but on reduced 1D sub-spaces

Postprint (published version)