Floquet Anomalous Edge States

A periodically driven 2D lattice hosts anomalous chiral edge modes with no bulk analog — the hallmark of Floquet topological phases. All bulk quasi-energy bands are trivial (Chern number = 0), yet robust chiral edge states traverse the entire quasi-energy zone.

Anomalous phase: Floquet systems can have C=0 bands yet still support chiral edge modes. The winding number W of the micromotion operator captures this. Edge states span ε ∈ [−π,π] with chirality determined by the drive protocol.
Phase: Anomalous