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 ^43Ca^+. We measure a combined qubit state preparation and single-shot readout fidelity of 99. 93%, a memory coherence time of T₂^*=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.