Superconducting architecture demonstrating fast, tunable high-fidelity CZ gates with parametric control of ZZ coupling

Future quantum information processors require tunable coupling architectures that can produce high-fidelity logical gates between two or more qubits. Parametric coupling is a powerful technique for generating tunable interactions between many qubits. Here, we present a highly flexible parametric coupling scheme with superconducting qubits that provides complete removal of residual ZZ coupling and the implementation of driven SWAP or SWAP-free controlled-Z (CZ) gates. Our fully integrated two-dimensional on-chip coupler design is only weakly flux tunable, cancels static linear coupling between the qubits, avoids internal coupler dynamics or excitations, and is extensible to multiqubit circuit-QED systems. Exploring gate fidelity versus gate duration allows us to maximize two-qubit gate fidelity, while providing insights into possible error sources for these gates. Randomized benchmarking over several hours reveals that the parametric SWAP CZ gate achieves an average fidelity of 99.44±0.09% in a gate duration of 70 ns and that a dispersively driven parametric SWAP-free CZ gate attains an average fidelity of 99.47±0.07% in only 30 ns. The fidelity remained above this value for over 8 h and peaked twice with a maximum of 99.67±0.14%. Overall, our parametric approach combines versatility, precision, speed, and high performance in one compact coupler design.