Demonstration of a Tuneable Coupler for Superconducting Qubits Using Coherent, Time Domain, Two-Qubit Operations

towards implementing a computer It is apparent that tuneable couplers will be an important building block for scaling up superconducting qubits because they interactions between qubits to be simply and directly controlled while avoiding frequency-crowding and residual coupling issues inherent to traditional frequency-tuned architectures Tuneable couplers have been demonstrated using superconducting qubits 16-18). However, these designs required the coupled/coupling elements to be in close proximity and showed either limited time-domain control or low on/off ratios making them difficult to scale up and of limited use in realistic qubit operations. We present a design which, for the first time in a single device, avoids these limitations. We experimentally show that using this tunable coupler, the inter-qubit coupling strength can be tuned with nanosecond time resolution and large on/off ratio within a sequence of qubit operations that