Okinawa Physicists Nudge Levitating Diamond With Light-Driven Electron Spin

OKINAWA, JAPAN — Researchers at the Okinawa Institute of Science and Technology (OIST) report that they have used the quantum spin of electrons to move a diamond held in levitation, according to a study published in Science Advances and summarized by The Debrief.

The apparatus, as described, centers on a diamond containing billions of nitrogen-vacancy centers, which are atomic defects that trap electrons whose spin can be controlled with light. The diamond was suspended above a magnet and joined to a levitating graphite plate by a carbon-fiber rod. Pulses of green laser light altered the electron spin states, producing small magnetic forces that set the assembly in motion.

The movement was measured to picometer precision by a laser interferometer, the report states. The paper's title refers to a 100-mg levitated resonator.

The team was careful to say what it had not done. According to the account, the experiment does not demonstrate quantum superposition in a macroscopic object. It does show that quantum spin can drive measurable mechanical motion in an object far larger than those used in earlier quantum experiments.

Large objects have long frustrated quantum physicists, the article explains, because vibration and heat tend to swamp delicate quantum effects. The researchers believe refinements could one day help probe the relationship between gravity and quantum mechanics, and yield sensors capable of detecting gravitational waves or dark matter.

OIST Professor Jason Twamley said in a statement: "All we need is another order of magnitude, and we can finally observe Schrödinger's cat in real life." The cat, for the moment, remains unobserved.