title: Universal quantum gate set approaching fault-tolerant thresholds with superconducting qubits.
abstract: 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.
authors.affiliation: IBM TJ Watson Research Center, Yorktown Heights, New York 10598, USA.
authors.forename: Jerry M
authors.initials: JM
authors.lastname: Chow
authors.forename: Jay M
authors.initials: JM
authors.lastname: Gambetta
authors.forename: A D
authors.initials: AD
authors.lastname: Córcoles
authors.forename: Seth T
authors.initials: ST
authors.lastname: Merkel
authors.forename: John A
authors.initials: JA
authors.lastname: Smolin
authors.forename: Chad
authors.initials: C
authors.lastname: Rigetti
authors.forename: S
authors.initials: S
authors.lastname: Poletto
authors.forename: George A
authors.initials: GA
authors.lastname: Keefe
authors.forename: Mary B
authors.initials: MB
authors.lastname: Rothwell
authors.forename: J R
authors.initials: JR
authors.lastname: Rozen
authors.forename: Mark B
authors.initials: MB
authors.lastname: Ketchen
authors.forename: M
authors.initials: M
authors.lastname: Steffen