Quantum Physics Meets Gravity: Scientists Move a Floating Diamond Using Electron Spins

By Gia Jing;

The Lawrenceville School, NJ

Quantum mechanics has a strange property: superposition, which states that particles can exist in multiple states at once. In 1935, physicist Erwin Schrödinger proposed a famous thought experiment. A cat sits inside a closed box with a radioactive atom, which is an unstable atom that can break apart or decay at any moment. If the atom decays, it triggers a device that releases poison into the box. Until someone opens the box, the atom remains in a superposition of decayed and not decayed. As a result, the cat can be considered both alive and dead at the same time. 

In the past, researchers at the Swiss Federal Institute of Technology in Zurich placed a 16-microgram mechanical resonator, a tiny vibrating crystal, into superposition in 2023. The resonator could vibrate in two opposite directions at once. On October 7, 2026, researchers at Japan’s Okinawa Institute of Science and Technology (OIST) reported that they successfully used only the force of electron spins (a quantum property that makes each electron act like a tiny compass needle) to move a levitating, centimeter-sized object. By demonstrating that electron spins can move a macroscopic object, the researchers at OIST established a potential pathway toward controlling the quantum behavior of larger objects, bringing scientists closer to experiments that could investigate the relationship between quantum mechanics and gravity.

Modern physics relies on two sets of rules: quantum mechanics and general relativity. Quantum mechanics explains the microscopic world and (sub)atomic phenomena, in which particles can spread across several places at once. On the other hand, general relativity, or Einstein’s theory of gravity, explains the macroscopic world, in which mass (gravity) bends spacetime (space and time). The key distinction is that general relativity describes gravity as the curvature of spacetime caused by mass and energy, while quantum mechanics allows particles to exist in superpositions of different states, including positions. Scientists have measured gravity's effects on quantum particles, but whether gravity itself behaves according to quantum mechanics is unresolved. One possible way to investigate this question is to create quantum superpositions of increasingly massive objects and study their gravitational interactions which comes with its own problem: heat and vibration can quickly erase quantum effects in large objects in a process called decoherence. The OIST team demonstrated that a quantum effect can move a macroscopic object by using electron spins to generate a magnetic force on an object heavy enough to feel gravity. The team used a 3-millimeter diamond containing billions of nitrogen-vacancy (NV) centers, which are flaws where a nitrogen atom sits next to a missing carbon atom and trap electrons with controllable spins. To levitate the setup in order to minimize the influence of environmental disturbance, the researchers used diamagnetism, which is the tendency of materials including graphite to push away from magnets. As such, the device contains a graphite plate floating above four magnets, with the diamond hanging below on a carbon fiber rod and above a separate magnet. 

Then, the team illuminated the diamond with a green laser periodically. Each flash changed the populations of the electrons' spin states, which strengthened the magnetic force subsequently pulling the diamond toward the magnet below. Between flashes, the pull weakened. The assembly then swung up and down by about 100 nanometers. With a mass of 128 milligrams, the assembly is “eight to nine orders of magnitude,” or 100 million to 1 billion times, heavier than objects moved by spin forces in earlier experiments, according to Professor Jason Twamley of the OIST Quantum Machines Unit, who led the team. Still, the assembly’s movement followed classical physics (how everyday objects behave), as it did not enter a quantum superposition. 

OIST expects the technology to yield sensors for searching for exotic forces (hypothetical, undiscovered forces of nature that may explain cosmic mysteries) or dark matter (an invisible substance that makes up most of the universe’s matter). Additionally, the breakthrough demonstrated that a small quantum effect can produce a large classical response, thus shifting the focus toward refining experimental conditions to achieve quantum superposition in a macroscopic object. Twamley argued that one more order of magnitude could make a real-life version of Schrödinger’s cat observable and potentially answer whether gravity obeys quantum rules. 

To transform the result into a true superposition, the researchers face several obstacles. The vibrations in the laboratory hide any movement smaller than about one nanometer, which limits the assembly’s measurement sensitivity. By shielding against those vibrations better, researchers can increase the sensitivity by up to three orders of magnitude. Furthermore, as the floating graphite plate moves above the magnets, tiny electric currents formed inside it act like brakes, which limits the motion of the assembly. The researchers proposed that replacing the original graphite plate with a composite diamagnetic structure to reduce damping, along with operating the assembly in a high vacuum environment, can improve the oscillator's motion. 

For nearly a century, Schrödinger’s cat has remained a thought experiment. Now, green lasers and tiny electron magnets can nudge an object big enough for people to hold. The OIST team has not created that cat in reality yet, but as Twamley said, the team is “pushing the bar from nanometers to centimeters.” Alongside future experiments, these results will help determine whether physics requires one set of rules or two. 

Works Cited

Bild, M., Fadel, M., Yang, Y., Von Lüpke, U., Martin, P., Bruno, A., & Chu, Y. (2023). Schrödinger cat states of a 16-microgram mechanical oscillator. Science, 380(6642), 274–278. https://doi.org/10.1126/science.adf7553

Choi, C. Q. (2017, November 6). A tabletop experiment for quantum gravity. Inside Science. https://www.aip.org/inside-science/a-tabletop-experiment-for-quantum-gravity

Nayak, A., Kim, D., Tian, S., & Twamley, J. (2026). Spin force from a nitrogen-vacancy ensemble drives a 100-mg levitated resonator. Science Advances, 12(41), Article eaeh0566. https://doi.org/10.1126/sciadv.aeh0566

Nield, D. (2026, October 10). For the first time ever, quantum spins shift a centimeter-scale object. Yahoo News. https://www.yahoo.com/news/science/articles/first-time-ever-quantum-spins-120000362.html

Okinawa Institute of Science and Technology. (2026, October 7). First observation of quantum spins shifting a centimeter-scale object in the lab. Okinawa Institute of Science and Technology OIST. https://www.oist.jp/news-center/news/2026/10/8/first-observation-quantum-spins-shifting-centimeter-scale-object-lab

Wolchover, N. (2018, March 6). Physicists find a way to see the ‘grin’ of quantum gravity. Quanta Magazine. https://www.quantamagazine.org/physicists-find-a-way-to-see-the-grin-of-quantum-gravity-20180306/