title: High-Fidelity Quantum Logic Gates Using Trapped-Ion Hyperfine Qubits.
abstract: We demonstrate laser-driven two-qubit and single-qubit logic gates with respective fidelities 99.9(1)% and 99.9934(3)%, significantly above the ≈99% minimum threshold level required for fault-tolerant quantum computation, using qubits stored in hyperfine ground states of calcium-43 ions held in a room-temperature trap. We study the speed-fidelity trade-off for the two-qubit gate, for gate times between 3.8  μs and 520  μs, and develop a theoretical error model which is consistent with the data and which allows us to identify the principal technical sources of infidelity.
authors.affiliation: Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom.
authors.forename: C J
authors.initials: CJ
authors.lastname: Ballance
authors.affiliation: Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom.
authors.forename: T P
authors.initials: TP
authors.lastname: Harty
authors.affiliation: Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom.
authors.forename: N M
authors.initials: NM
authors.lastname: Linke
authors.affiliation: Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom.
authors.forename: M A
authors.initials: MA
authors.lastname: Sepiol
authors.affiliation: Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom.
authors.forename: D M
authors.initials: DM
authors.lastname: Lucas