Description
Levitated macroscopic particles exhibiting quantum mechanical effects are garnering increased attention as a means for precision sensing and testing quantum mechanics. Defects in diamond, such as the nitrogen-vacancy (NV) centre possess optically-addressable spins with long coherence times at room temperature and offer an intriguing system to examine quantum spin dynamics coupled to a macroscopic classical particle. In this work, we convert the outcome of a quantum measurement on an ensemble of spins in diamond into a macroscopic rotation of the host particle via spin-mechanical coupling [1]. Following a sequence of green laser and microwave control pulses, spin-mechanical coupling between the final qubit spin state and the host particle – an electrically-levitated diamond – exerts a torque on the particle that deflects a weak near-infra-red laser beam. We measure spin readout contrast in excess of 70%, and demonstrate pulsed mechanical detection of coherent Rabi oscillations, spin-echo interferometry and T1-induced relaxation. We directly measure, with temporal resolution, the particle reorientation from a 60 attonewton-metre spin torque induced by flipping the spins. Our results open up interesting new opportunities for levitated spin-mechanical systems using pulsed control. I will also discuss other recent results from our research group, from examining the coupling between multiple trapped microparticles to the use of silica-coated nanodiamond particles to prevent laser-induced oxidation of optically trapped nanodiamonds.
[1] A. A. Wood et al, arXiv:2603.02507 (2026).
| I am the presenting author | Yes |
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