Fast parametric two-qubit gates for fixed-frequency qubits and tunable couplers, part 2: experiment

Quantum processors with fixed-frequency qubits and parametric two-qubit gates are good candidates for scaling up as they use comparatively few flux-lines and provide a versitile, large native gate set. However, parametric gates are typically slow compared to other two-qubit gates. Short gate times are important as they determine the runtime of quantum algorithms and set an upper limit for the gate fidelity. Here, we utilize a novel method for choosing gate parameters to drive a parametric iSWAP gate considerably faster than conventional parametric gates.

To characterize the gate, we use unitary tomography and interleaved randomized benchmarking. We also further investigate gate errors such as ZZ coupling, qubit coherence, and leakage.