Controlling Nuclear Spin Without Radio Waves express

Original: "RF-free driving of nuclear spins with color centers in silicon carbide"
arXiv:2601.21499 · 2026-01-29 · CC BY 4.0 · 1 min
The nuclear spin obeys the same microwaves as the electron spin.

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A quantum computer is like an orchestra where electrons and nuclei play different instruments. Usually, the conductor needs two batons: microwaves for electrons and radio waves for nuclei. Scientists from Japan found a way to get by with just one baton: they made microwave pulses control both the nucleus and the electron simultaneously.

In a silicon carbide crystal, they created a defect — a spot where atoms are arranged differently than in the rest of the crystal. Such a defect acts as a trap for an electron, and next to it sits a silicon nucleus. The electron spin (its intrinsic rotation, like a spinning top) usually responds to microwaves, while the nuclear spin responds only to radio waves. But if you tilt the external magnetic field at a precise angle, the coupling between them sharply increases. Now, when a microwave pulse flips the electron spin, it also nudges the nucleus.

The accuracy of nuclear spin control reached 89%—that's like hitting the bullseye from several meters away.

This trick saves energy and simplifies the quantum device's architecture. No more separate wires for radio signals or bulky amplifiers. Quantum memory based on nuclear spins lasts almost as long as the material itself allows — the time it takes for the nuclear spin to lose its orientation approaches the theoretical limit. This matters for quantum sensors that already measure magnetic fields in living cells or search for minerals underground. Instead of complex equipment, just one microwave source and a precisely tilted magnet.

Nuclear spin can store quantum information thousands of times longer than electron spin, because the nucleus is less affected by environmental noise.

In the series 'Devs,' a quantum computer is controlled by microwaves, but to work with nuclei, the characters would have had to add radio transmitters — here, that problem is solved.

Scientists
Enrico FermiPaul DiracDavid DeutschErwin SchrödingerJohn Stewart BellLouis de Broglie
Concepts
nuclear spin spectroscopy single spin manipulation semiconductor qubits neutral atom quantum computer rubidium control signal solid state qubit carbon 13 quantum qubit engineering strontium radio pulse silicon chip spintronics photonic integrated circuit silicon carbide radical pair diamond nv center spectroscopy microwave pulse hybrid system color charge