Japan achieves near-frictionless levitation on macroscopic rotor

A research team at the Okinawa Institute of Science and Technology (OIST) has developed a groundbreaking graphite-only levitating rotor that eliminates eddy-current damping, a major source of energy loss in macroscopic levitating systems. By using a one-centimeter graphite disk with rare-earth magnets and leveraging axial symmetry, the rotor spins freely without resistance from eddy currents, which typically arise when conductive materials move through changing magnetic fields. This innovation preserves strong levitation strength while removing friction-like damping, overcoming limitations of previous designs that mixed graphite with other materials and weakened levitation. The key to this advancement lies in the rotor’s rotational symmetry, which keeps it within a constant magnetic flux during rotation, preventing eddy currents from forming. This contrasts with earlier plate designs that experienced damping due to fluctuating magnetic flux when moving vertically. The team confirmed their findings through simulations, mathematical proofs, and experiments, showing that performance now hinges on maintaining perfect axial symmetry and minimizing air friction by operating in near-vacuum conditions