Superconducting-qubit coupler design with exponentially large on-off ratio

We present a design for a superconducting-qubit coupler featuring an exponentially large on-off ratio that is controlled by the amplitude of a microwave drive. In this architecture, the tunable bus interacts with a driven mode such as to, on demand, exponentially suppress the qubit-qubit virtual interactions with respect to the amplitude of the external control field. We demonstrate how this scheme can be used to reduce residual cross-Kerr (or~ZZ) interactions in transmon-qubit-based quantum processors. We also provide a superconducting-circuit implementation of the coupler, which can enable high-fidelity parametric two-qubit gates and help to reduce cross-talk.