Changing the spin state of electrons has produced measurable motion in a levitated diamond system. Researchers at Japan's Okinawa Institute of Science and Technology described the experiment on October 8, linking a quantum effect to a much larger mechanical response.
Spin is an intrinsic quantum property that makes an electron behave like a tiny magnet. The diamond contains nitrogen-vacancy centers, defects in its crystal structure that hold unpaired electrons whose spin can be controlled.
The team periodically illuminated the diamond with a green laser. That changed the collective spin state and its magnetic behavior, producing a small force that moved the system.
The experimental assembly connected the diamond to a levitated graphite plate through a carbon-fiber rod. Magnetic shielding separated parts of the setup. A mirror on the plate let an interferometer measure motion through changes in reflected light.
OIST describes a 50-milliwatt excitation laser and displacement measurements with picometer precision. The paper concerns a 100-milligram levitated resonator. That is a mechanical system responding to a spin-generated force, not an entire object demonstrated in quantum superposition.
This limit separates the measured result from the researchers' longer-term aim. Putting a sufficiently massive object into a superposition of distinct positions would be a further experiment, with additional demands on isolation and control.
The present work supplies a way to transfer a controlled spin response into motion that can be measured mechanically. The observed displacement is the result.
