Memory coherence of a sympathetically cooled trapped-ion qubit
Memory coherence of a sympathetically cooled trapped-ion qubit
We demonstrate sympathetic cooling of a ${^{43}\text{C}\text{a}}^{+}$ trapped-ion ``memory'' qubit by a ${^{40}\text{C}\text{a}}^{+}$ ``coolant'' ion sufficiently near the ground state of motion for fault-tolerant quantum logic, while maintaining coherence of the qubit. This is an essential ingredient in trapped-ion quantum computers. The isotope shifts are sufficient to suppress decoherence and …