One promising approach for quantum information processing involves embedding tightly spaced arrays of identical atomic nuclei in a silicon substrate. In that design, each nucleus’s spin serves as a quantum bit, or qubit. The qubit’s spin, which can be set to different states, is used to store and process information. However, before spin-based devices can be scaled up for practical use, quantum engineers need to be able to control a single nuclear spin in silicon without affecting adjacent spins.

In principle, NMR could do the job. Radio-frequency (RF) magnetic field pulses can excite and control nuclear spins that are polarized in a static magnetic field. Because of the pulses’ wide spatial extent, however, they tend to influence adjacent spins, which renders NMR impractical for manipulating individual spins in a collection of identical atoms. Ideally, a method for controlling individual nuclear spins would match the ease of exciting individual electron spins...

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