Universal Quantum Gate Set Approaching Fault-Tolerant Thresholds with Superconducting Qubits
Jerry M. Chow, Jay Gambetta, Antonio D. Corcoles, Seth Merkel, John A. Smolin, Chad T. Rigetti, Stefano Poletto, George Keefe, Mary Beth Rothwell, John Rozen, M. B. Ketchen, Matthias Steffen · Physical Review Letters · 2012
We use quantum process tomography to characterize a full universal set of all-microwave gates on two superconducting single-frequency single-junction transmon qubits. All extracted gate fidelities, including those for Clifford group generators, single-qubit π/4 and π/8 rotations, and a two-qubit controlled-not, exceed 95% (98%), without (with) subtracting state preparation and measurement errors. Furthermore, we introduce a process map representation in the Pauli basis which is visually efficient and informative. This high-fidelity gate set serves as a critical building block towards scalable architectures of superconducting qubits for error correction schemes and pushes up on the known limits of quantum gate characterization.