Levitated Silica Magnet Spins at 1.2 GHz, Setting Record for Macroscopic Rotors
A levitated nanoscale magnet achieved record spin speeds, demonstrating new sensitivity for fundamental physics tests. The experiment highlights optical levitation's potential but requires multi-particle validation before broad claims.
Researchers trapped the particle using optical tweezers and applied a rotating magnetic field to accelerate it while monitoring rotation via scattered light. The setup achieved stable spin rates exceeding prior macroscopic rotors by more than an order of magnitude, with torque sensitivity reaching 10^-24 Nm. Data came from a single-particle trap operated over weeks with active feedback cooling.
The work extends earlier levitation techniques used in tests of gravity at short ranges and searches for dark matter couplings. It improves on 2022 results with charged rotors by removing electrostatic noise, enabling longer coherence times. Potential applications include torque magnetometry for quantum materials and tests of quantum gravity models at the Planck scale.
A key limitation is the reliance on a single particle in idealized vacuum conditions; environmental coupling and particle-to-particle variability remain untested. Scaling to arrays or integrating with superconducting circuits would strengthen claims for quantum technology use.
Next steps involve coupling the rotor to superconducting qubits to probe spin-phonon interactions and repeating measurements in a cryogenic environment to reduce thermal noise below 1 mK.
Sources (2)
- [1]Primary Source(https://www.nature.com/articles/s41567-024-02489-3)
- [2]Supporting Source(https://arxiv.org/abs/2403.14567)