Observation of Antichiral Edge States in a Circuit Lattice

We constructed an electrical circuit to realize a modified Haldane lattice exhibiting the unusual phenomenon of antichiral edge states. The circuit consists of a network of inductors and capacitors with interconnections reproducing the effects of a magnetic vector potential. The next nearest neighbor hoppings are configured differently from the standard Haldane model, and as predicted by earlier theoretical studies, this gives rise to antichiral edge states that propagate in the same direction on opposite edges and co-exist with bulk states at the same frequency. Using pickup coils to measure the voltage distributions in the circuit, we experimentally verify the key features of the modified Haldane lattice, including the group velocities of the antichiral edge states.