High-fidelity elementary qubit operations with trapped ions
Optica Publishing Group (2017) qw6a.1
High-Fidelity Trapped-Ion Quantum Logic Using Near-Field Microwaves.
Physical review letters 117:14 (2016) 140501-140501
Abstract:
We demonstrate a two-qubit logic gate driven by near-field microwaves in a room-temperature microfabricated surface ion trap. We introduce a dynamically decoupled gate method, which stabilizes the qubits against fluctuating energy shifts and avoids the need to null the microwave field. We use the gate to produce a Bell state with fidelity 99.7(1)%, after accounting for state preparation and measurement errors. The gate is applied directly to ^{43}Ca^{+} hyperfine "atomic clock" qubits (coherence time T_{2}^{*}≈50  s) using the oscillating magnetic field gradient produced by an integrated microwave electrode.High-fidelity trapped-ion quantum logic using near-field microwaves
(2016)
High-fidelity quantum logic gates using trapped-ion hyperfine qubits
Physical Review Letters American Physical Society 117:6 (2016) 060504
Abstract:
We demonstrate laser-driven two-qubit and single-qubit logic gates with fidelities 99.9(1)% and 99.9934(3)% respectively, significantly above the ≈ 99% minimum threshold level required for faulttolerant 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.Dark-resonance Doppler cooling and high fluorescence in trapped Ca-43 ions at intermediate magnetic field
New Journal of Physics IOP Publishing 18:2 (2016) 023043