Okinawa Researchers Propel 128-Milligram Levitating Diamond Using Only Quantum Electron Spin

On October 7, 2026, researchers at the Okinawa Institute of Science and Technology demonstrated that the quantum spin of electrons can physically move a 128-milligram levitating object. Published in Science Advances, the experiment marks the first time a quantum force has driven a macroscopic mass.[1][5]

The object is eight to nine orders of magnitude more massive than those used in previous spin-mechanical experiments. By scaling up the mass, the research bridges the microscopic domain of quantum mechanics and the macroscopic world governed by classical physics and gravity.[1][2]

Testing how quantum mechanics and general relativity interact requires observing quantum effects in objects heavy enough to generate a meaningful gravitational pull. Heat, vibration, and environmental noise typically destroy delicate quantum states long before an object reaches that scale.[1]

Previous attempts to cross this boundary usually started small, trying to add mass to nanometer-scale objects suspended in optical traps. The Okinawa team took the opposite approach, starting with a heavy, centimeter-scale object and working down toward quantum control.[1]

“We’ve shown a large classical response from a small quantum effect,” said Professor Jason Twamley, head of the OIST Quantum Machines Unit. “It’s no longer a question of whether such technology is possible, but of how we can refine experimental conditions.”[1][2]

Engineering a Macroscopic Resonator

The experimental apparatus relies on diamagnetic levitation. A slotted graphite plate floats above a checkerboard array of permanent magnets. A rigid carbon-fiber rod extends downward from this plate, passing through a layer of magnetic shielding to isolate the payload below.[1][4]

At the bottom of the rod hangs a centimeter-scale diamond. The entire suspended assembly weighs exactly 128 milligrams, functioning as an integrated mechanical resonator. It possesses a natural vertical oscillation frequency of 17.6 hertz, making it highly responsive to periodic forces.[4]

The diamond is engineered to contain billions of nitrogen-vacancy centers. These are specific atomic defects where a nitrogen atom replaces a carbon atom adjacent to an empty space in the crystal lattice, creating a trap for unpaired electrons.[1][3]

Because diamond features weak spin-orbit coupling, these trapped electrons are largely shielded from environmental interference. This isolation allows the nitrogen-vacancy centers to maintain their quantum spin states at room temperature far longer than competing solid-state systems.[1]

Translating Spin Into Motion

To manipulate these electrons, the researchers fired a 50-milliwatt green laser at the diamond. By pulsing the laser at 17.6 hertz to match the assembly’s mechanical resonance, they synchronized the spin states of billions of trapped electrons simultaneously.[1][4]

When the laser polarized the nitrogen-vacancy centers, the collective magnetic moment of the electrons shifted. Interacting with the static magnetic field gradient generated by a cylindrical magnet placed beneath the diamond, this spin change produced a physical downward force.[1][4]

An optical interferometer measured the resulting movement by bouncing a separate laser off a mirror mounted on the levitating graphite plate. The instrument tracks displacement with picometer precision, capable of detecting shifts equivalent to trillionths of a meter.[1][3]

The measurements revealed that the periodic spin force drove the 128-milligram assembly to oscillate with an amplitude exceeding 100 nanometers. This physical displacement represented a massive classical response to the microscopic state of the trapped electrons.[2][4]

To confirm the movement was genuinely driven by quantum spin rather than thermal expansion from the laser, the team ran control tests. When they removed the magnetic field gradient or used an infrared laser that cannot polarize the spins, the large oscillations vanished.[1][4]

The Path to Schrödinger's Cat

“Now, we have observed a classical mechanical response to a quantum force on an object that is eight to nine orders of magnitude more massive than the current state-of-the-art,” Twamley said, confirming the successful scaling of the spin-mechanical effect.[2]

While the experiment translated a quantum force into classical motion, it did not place the diamond itself into a quantum state. The physical movement observed was a classical response to the quantum behavior of the electrons housed inside the crystal.[2]

The next major hurdle is achieving genuine macroscopic superposition—forcing the entire 128-milligram diamond to exist in two distinct positions simultaneously. This would realize a literal Schrödinger's cat scenario, where a massive object occupies multiple states until observed.[1][2]

“We’re pushing the bar from nanometers to centimeters,” Twamley noted regarding the team's future trajectory. “All we need is another order of magnitude, and we can finally observe Schrödinger's cat in real life, testing the limits of Einstein's general relativity.”[1][2]

Reaching that state requires extreme environmental isolation. The team must further shield the levitating resonator from ambient heat and microscopic vibrations. These external disturbances rapidly destroy delicate quantum superpositions through a process known as decoherence, collapsing the dual states into one.[1]

Practical Sensor Applications

Beyond fundamental physics, this spin-mechanical coupling offers immediate practical applications. The extreme sensitivity of the nitrogen-vacancy centers to external magnetic fields makes the levitating diamond an extraordinarily precise sensor, capable of detecting minute forces and displacements that other instruments miss.[1]

Future iterations of this technology could be deployed to map microscopic magnetic fields in biological samples or detect gravitational waves. Researchers also anticipate using similar ultrasensitive devices to search for the faint gravitational signatures of dark matter.[3]

For now, the Okinawa experiment establishes a new mechanical baseline. By proving that quantum spin can reliably drive a macroscopic mass, physicists have built a concrete platform for testing the boundary where quantum mechanics meets the macroscopic universe.[1][4]