Achieving high contrast on/off ratios using the multipole circuit QED architecture

An outstanding goal for scalable quantum information processing is to design gates (qubit-qubit interactions) that are fast, yet can be switched off with high contrast to permit high fidelity single qubit operations. We implement a possible candidate for such a gate using the multipole circuit QED architecture which consists of superconducting Josephson junction qubits coupled via multiple strongly interacting microwave cavities. In this architecture, the on/off ratio is expected to scale exponentially in the number of cavities (poles). Here we report on measurements of the off-resonant coupling rate for two flux-tuned transmon qubits coupled through three strongly coupled planar resonators (a 3-pole filter). We will also discuss progress towards a scheme to implement multipole QED for flux insensitive qubits in 3D microwave cavities where the longest coherence times for superconducting qubits have been demonstrated.