Electron spins push a centimeter-wide diamond floating above a magnet
A Japanese team used the spin of electrons trapped in diamond defects to push an object billions of times heavier than earlier spin-mechanical tests used.
By
Ethan Reid
In brief
- OIST researchers moved a levitating, centimeter-wide diamond using only the force from electron spin.
- The results appear in Science Advances in a paper led by PhD student Anshuman Nayak.
- Motion was tracked by laser interferometry with picometer precision.
- The team describes the setup as a platform for testing exotic physics theories, with future sensors as a prospect.
A force produced by nothing more than the spin of electrons has pushed a diamond about a centimeter across, floating above a magnet, and the shift was large enough to measure. According to Phys.org, which relayed the announcement from the Okinawa Institute of Science and Technology (OIST), this marks the first time a quantum effect has been seen directly manipulating an object subject to gravity.
Scale is what makes the result stand out. Quantum mechanics sits behind lasers, MRI scanners, semiconductors and quantum computers, yet most research in the field has dealt with atoms and smaller particles, far beyond anything people can perceive. Professor Jason Twamley of the OIST Quantum Machines Unit says the moving object is eight to nine orders of magnitude more massive than those used in today’s leading spin-mechanical experiments.
“We’ve shown a large classical response from a small quantum effect.”
Jason Twamley, professor, OIST Quantum Machines Unit
Why big objects resist quantum behavior
The obstacle is mostly environmental. Compared with nanoscopic particles, large objects are far harder to shield from heat and vibration, and that noise swamps delicate quantum signals. Gravity poses the mirror-image problem: it anchors general relativity, but at the nanometer scale where quantum effects have been recorded, its pull is extremely weak. Positional superposition, in which a particle occupies distinctly different places at once until it is measured, has so far been shown experimentally only at the microscopic level.
Twamley summed up the state of play bluntly: “There have been many efforts to test whether quantum mechanics holds for anything larger than a few tens of nanometers, so far without success.”
Most groups try to bridge that gap by levitating tiny objects and gradually adding mass. First author Anshuman Nayak, a PhD student in the unit, says lifting macroscale objects with optical traps has proven extremely difficult, so the team relies on diamagnetic levitation instead. “That’s why we’re in the opposite camp, going from large to small,” he said.
How the experiment works, step by step
The researchers assembled the apparatus from smaller devices they had recently demonstrated on their own. In sequence:
- A graphite plate carrying a small mirror floats through diamagnetic levitation.
- A carbon rod runs from that plate through magnetic shielding to a diamond suspended above a magnet.
- The diamond holds billions of nitrogen-vacancy (NV) centers, defects that trap unpaired electrons and behave as tiny quantum magnets whose spin force can be controlled.
- Pulses of green laser light set those centers into a chosen spin state, creating small magnetic fluctuations that press the diamond downward.
- An interferometer bounces a laser off the mirror on the graphite plate, registering changes in distance down to picometers.
The choice of material was deliberate. Co-author Daehee Kim, also a PhD student in the unit, notes that NV centers have some of the longest coherence times known, keeping quantum superposition alive at room temperature longer than other systems. “NV diamonds are well understood and easy to control,” he said.
What the result does and does not show
The diamond itself was not placed in a quantum superposition. What the team recorded is a classical mechanical response to a force of quantum origin. By isolating a mechanical effect that stems from quantum spin alone, the OIST group says it has built an experimental platform for testing exotic theories of physics.
The work, published in Science Advances under the title “Spin-force from a Nitrogen-Vacancy ensemble drives a 100 mg levitated resonator” (Nayak et al., 2026), is presented by its authors as a new baseline for probing where classical physics ends and quantum physics begins. They also point to a possible class of highly accurate sensors aimed at dark matter, gravitational waves and other exotic phenomena, a prospect rather than an instrument that exists today.
Photo: Edward Jenner / Pexels
