We present a scalable architecture for the exploration of interacting topological phases of photons in arrays of microwave cavities, using established techniques from cavity and circuitquantum electrodynamics. A time-reversal symmetry breaking (non-reciprocal) flux is induced by coupling the microwave cavities to ferrites, allowing for the production of a variety of topological band structures including the α=1/4 Hofstadter model. Effective photon-photon interactions are included by coupling the cavities to superconducting qubits, and are sufficient to produce a ν=1/2 bosonic Laughlin puddle. We demonstrate by exact diagonalization that this architecture is robust to experimentally achievable levels of disorder. These advances provide an exciting opportunity to employ the quantum circuit toolkit for the exploration of strongly interacting topological materials.
Superconducting circuits have emerged as a configurable and coherent system to investigate a wide variety of quantum behaviour. This architecture — circuit QED — has beenused to demonstrate phenomena from quantum optics, quantum limited amplification, and small-scale quantum computing. There is broad interest in expanding circuit QED to simulate lattice models (e.g., the Jaynes-Cummings-Hubbard model), generate long-distance entanglement, explore multimode quantum optics, and for topological quantum computing. Here we introduce a new multi-resonator (multi-pole) circuit QED architecture where qubits interact through a network of strongly coupled resonators. This circuit architecture is a novel system to study multimode quantum optics, quantum simulation, and for quantum computing. In this work, we show that the multi-pole architecture exponentially improves contrast for two-qubit gates without sacrificing speed, addressing a growing challenge as superconducting circuits become more complex. We demonstrate the essential characteristics of the multi-pole architecture by implementing a three-pole (three-resonator) filter using planar compact resonators which couples two transmon-type qubits. Using this setup we spectroscopically confirm the multimode circuit QED model, demonstrate suppressed interactions off-resonance, and load single photons into the filter. Furthermore, we introduce an adiabatic multi-pole (AMP) gate protocol to realize a controlled-Z gate between the qubits and create a Bell state with 94.7% fidelity.