Scientists from Okinawa Institute of Science and Technology (OIST) have created a levitating rotor that rotates with virtually no loss of energy. The new system eliminated the main barrier that prevented achieving ideal levitation – the so-called eddy current damping. This opens the way to the creation of ultra-precise sensors, gyroscopes, and even experiments in quantum physics. The results were published in Communications Physics.

How a graphite disk levitates

Levitation is not a magician’s trick, but a technique long ago mastered by physicists that allows objects to be isolated from friction and vibration. Usually, magnets and materials that can be repelled from them are used for this. However, when conducting bodies move in a magnetic field, eddy currents arise – microscopic electric circles that create resistance and inhibit movement.

The OIST team has found a way to get rid of this problem. They used light graphite disk with a diameter of one centimeterwhich floats above three permanent magnets. Thanks to its perfectly symmetrical shape, the rotor does not cross areas with different magnetic strengths and therefore does not create braking eddy currents.

“We have experimentally shown that a graphite rotor can levitate without any signs of eddy current attenuation. If we can slow down the rotation to the quantum level, such a system could become a new platform for quantum experiments,” explained the graduate student Kim in thefirst author of the work

Why didn’t previous systems work?

Previously, physicists tried to reduce resistance by adding silica powder and wax to graphite. This limited the eddy currents, but weakened the levitation itself. Completely new option graphitetherefore maintaining repulsion force and stability in the air.

“When the plate moves up and down, the magnetic flux changes and eddy currents are created within the material. But the rotating rotor remains in a constant field – the flow does not change, and friction disappears,” explained project leader Professor Jason Tuemley

To test the hypothesis, scientists used computer modeling, mathematical calculations and laboratory experiments. It turned out that the effectiveness of levitation is now limited only by air friction – it can be minimized if experiments are carried out in a vacuum.

From laboratory to quantum sensors

The technology has potential far beyond academic research, Tuemley said.

“Our levitating rotor is ideal for ultra-precise sensors and gyroscopes. If you increase the rotation speed, it will become a stable navigation device. If you slow it down, you can enter the quantum mode, where movement obeys the laws of quantum mechanics.”

Previously, a prototype of the OIST levitating system had already been in space as a test for future experiments to search for dark matter and gravitational waves. The new version – more stable and free of damping – can make such studies even more accurate.