Spin force from a nitrogen-vacancy ensemble drives a 100-mg levitated resonator

Abstract

The force experienced by a spin in a magnetic field gradient underlies many proposals for hybrid quantum systems. These include schemes for mechanically mediated quantum gates, spin squeezing, searches for exotic forces, and motional superpositions for probing the interface between quantum and gravity. Yet, experimentally observing this spin force for anything larger than atomic scales has proved challenging. In our work, we demonstrate controllable center-of-mass motion of a 128-milligram diamagnetically levitated oscillator due to force from an ensemble of nitrogen-vacancy (NV) defects in diamond. We induce coherent motion in the oscillator by periodic optical initialization of the NV spin states, achieving motional amplitudes exceeding 100 nanometers. Our results mark a key milestone toward spin-based engineering of motional states deep in the high-mass regime.