High-Fidelity Preparation, Gates, Memory, and Readout of a Trapped-Ion Quantum Bit
T. P. Harty, D. T. C. Allcock, Christopher J. Ballance, Luca Guidoni, H. A. Janacek, Norbert M. Linke, D. N. Stacey, D. M. Lucas · Physical Review Letters · 2014
We implement all single-qubit operations with fidelities significantly above the minimum threshold required for fault-tolerant quantum computing, using a trapped-ion qubit stored in hyperfine "atomic clock" states of ^{43}Ca^{+}. We measure a combined qubit state preparation and single-shot readout fidelity of 99.93%, a memory coherence time of T_{2}^{*}=50 sec, and an average single-qubit gate fidelity of 99.9999%. These results are achieved in a room-temperature microfabricated surface trap, without the use of magnetic field shielding or dynamic decoupling techniques to overcome technical noise.