High-fidelity preparation, gates, memory and readout of a trapped-ion   quantum bit
  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 $T^*_2=50$ seconds, 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. 
T. P. Harty, D. T. C. Allcock, C. J. Ballance, L. Guidoni, H. A.   Janacek, N. M. Linke, D. N. Stacey and D. M. Lucas
quant-ph