There is another notable development in the field of quantum physics to report on, and it has to do with electron spin: the small built-in magnetism of these particles, as if each carried a microscopic compass needle. Previously, the strength of these spins alone had proven to be enough to push individual atoms in one direction or another. Now, however, researchers have managed to change something much, much bigger. A team from the Okinawa Institute of Science and Technology (OIST) in Japan has published a new study in Science Advances that details how these quantum forces can push a centimeter-sized object. It is an important step forward for science at the limit of the quantum (very small scales) and the classical (everything else). Crucially, the experiment deals with an object large enough to be subject to gravity, a fundamental force that has not always sat well with theories of quantum physics. “There have been many efforts to test whether quantum mechanics is valid for anything larger than a few tens of nanometers, so far without success,” says theoretical physicist Jason Twamley. “Now, we have observed a classical mechanical response to a quantum force in an object that is eight to nine orders of magnitude more massive than current state-of-the-art spin mechanical experiments.” The researchers combined several smart experimental design choices to get their results, starting with the centimeter-sized object: a graphite plate, placed on a levitating board of magnets. A diagram showing the setup of the motion experiment. (Nayak et al., Sci. Adv. 2026) Hanging from the plate was a 3-millimeter diamond with special atomic defects known as nitrogen vacancy (NV) centers. These defects give the diamond electrons with controllable spins, which were then manipulated with laser light. Another magnet was then used to convert those spins into motion. The whole thing weighed about 128 milligrams (that’s just a few grains of rice) and was pushed about 100 nanometers, about one-thousandth of a human hair. It’s not much, but it’s enough. “NV diamonds are well known and easy to control,” says physicist Daehee Kim. “This, and the fact that NV centers have some of the longest coherence times known, allowing them to maintain quantum superposition at room temperature for much longer than other systems, makes them particularly attractive for generating macroscopic motion or object superpositions in future research.” With the help of laser light, the diamond was shifted by 100 nanometers. (Nayak et al., Sci. Adv. 2026) When it comes to reconciling the massive (something like the effect of gravity on a planet) with the subatomic and quantum, scientists often try to start small and then work their way up. In this case, the study team took the opposite approach: their facility was not planet-sized, but rather very large in quantum terms. “We are in the opposite camp: we are going from big to small,” says physicist Anshuman Nayak. “Just as diamagnetic levitation can lift maglev trains, it can also be used to levitate centimeter-wide objects containing diamonds, where the effect of gravity can be extremely strong, but no quantum effects have been observed.” research, for those of us who are not physicists may seem quite esoteric and distant, but reaching milestones like this will help us answer some of the deepest questions about the Universe, including whether or not gravity follows quantum rules. It’s worth keeping in mind that the movement here was classical: what was important was the quantum effect that triggered the movement. Going forward, the researchers hope their approach can help put larger objects into quantum states, such as superposition, where they effectively occupy two states at once. “We have shown a large classical response from a small quantum effect,” says Twamley. “It is no longer a question of whether this technology is possible, but rather how we can refine the experimental conditions to achieve quantum superposition within the regime of Einstein’s general relativity.” “We are pushing the bar from nanometers to centimeters. All we need is another order of magnitude, and we will finally be able to observe Schrödinger’s cat in real life.” The research has been published in Science Advances. This article was fact-checked by Fiona MacDonald and edited by Fiona MacDonald. While we take pride in our process, we are human. If you spot an error, please let us know.
