Extended Data Fig. 1: System details. | Nature

Extended Data Fig. 1: System details.

From: Demonstration of the trapped-ion quantum CCD computer architecture

Extended Data Fig. 1

a, Close-up schematic of the trap region used in this work. Dimensions are in micrometres. We refer to the orange gating region on the left as zone 1 and the blue gating region as zone 2. b, Transport primitive library and associated heating estimates. For the estimates, we fit four ion-crystal spin-flip data to a model that assumes that all modes are at the same temperature. The fitted temperature increases are converted to units of quanta/mode (we note that the inequality holds for all modes). The times shown do not include interpolation between different operations or small delays in the electronics, which increase the time for every operation by ~10%. The interzone shift is a linear shift between the two gate zones, whereas an intrazone shift moves ions within a single gate zone by 110 μm for single-qubit addressing. c, Times for qubit operations, transport and cooling. Circuits can be run using two different measurement protocols. For circuits in which all measurements are made at the end, we use the high-fidelity measurement setting. Circuits containing mid-circuit measurements use shorter-duration measurements to minimize the crosstalk error on idle qubits. The shorter detection time measurement error is ~7 × 10−3, about twice as large as those reported in Table 1. Mid-circuit measurements induce an error of ~1% on neighbouring idle qubits, as measured by a Ramsey experiment. There are three different cooling stages used during transport (stages 1 and 2) and before gates (stage 3) and are either implemented through Doppler or sideband (SB) cooling. d, Construction of a phase-insensitive TQ gate. The Mølmer–Sørensen interaction generates the unitary \({U}_{{\rm{MS}}}=\exp [-{\rm{i}}\frac{{\rm{\pi }}}{4}{(X\sin \varphi +Y\cos \varphi )}^{\otimes 2}]\) (orange), whose basis is determined by the optical phase ϕ. SQ operations driven by the same laser beams generate the unitary \({U}_{{\rm{SQ}}}=\exp [-{\rm{i}}\frac{{\rm{\pi }}}{4}(X\cos \,\varphi +Y\sin \,\varphi )]\) (blue) and are applied globally to both qubits. The resulting composite gate is, up to a global phase, given by \({U}_{zz}=\exp (-{\rm{i}}\frac{{\rm{\pi }}}{4}Z\otimes Z)\) (green).

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