Engineering Flat-Band Lattices with Superconducting Circuits

Many strongly interacting many-body phenomena may be intimately related to the presence of flat electronic bands. Engineering lattices with such bands, however, requires precise and accurate control over lattice site connectivity along with minimal disorder. Superconducting circuits provide a flexible architecture to realize tight-binding Hamiltonians with flat bands by placing qubits in near-arbitrary lattice configurations. The qubit nonlinearity provides effective on-site interactions between photons to access the strongly interacting many-body regime. We present our experimental realization and characterization of a single plaquette of the rhombus chain flat-band lattice and introduce an artificial gauge field to realize a plaquette of an all-flat-band lattice.