On isospectral potentials on periodic discrete graphs

We consider discrete Schrödinger operators with periodic (possibly complex valued) potentials Q on periodic graphs. Using a system of spectral invariants obtained in {S26}, we investigate the sets of isospectral potentials on periodic graphs. In particular, we show that the Floquet spectrum of the Schrödinger operators on the hexagonal lattice and on the Kagome lattice generically (with respect to perturbations of Q) determines the potential Q uniquely up to the obvious symmetries (translations and rotations) in the periodic graph.