Harty TP, Allcock DTC, Ballance CJ, Guidoni L, Janacek HA, Linke NM, Stacey DN, Lucas DM
摘 要
The great potential of quantum computing requires two essential ingredients for its realization: high-fidelity quantum logic operations and a physical implementation which can be scaled up to large numbers of quantum bits. We introduce a trapped-ion qubit stored in ultrastable \"atomic clock\" states of $^{43}$Ca$^+$, in which we implement all single-qubit operations with fidelities sufficient for fault-tolerant quantum computing. 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 device without the use of magnetic field shielding or dynamic decoupling techniques to overcome technical noise. The surface-electrode ion trap chip incorporates integrated resonators and waveguides for coherent manipulation of the qubit using near-field microwaves. Two-qubit gates and individual qubit addressing have already been demonstrated using this approach, which is scalable for a many-qubit architecture.