Optomechanics with a Particle in a Magneto-Gravitational Trap

Optomechanical systems consisting of a levitated object whose motion is optically measured or controlled are attractive for their simplicity and extreme isolation from their environment. We are pursuing several experiments with microparticles in magneto-gravitational traps, which use a combination of diamagnetism and the earth's gravity. First, the center-of-mass motion of the particle can be cooled to temperatures far below the ambient temperature using feedback, potentially leading to fundamental tests of quantum mechanics. Second, the change in the frequency of oscillation of the particle under the influence of field masses can be used to measure the Newtonian constant of gravitation. Finally, trapped silicon carbide microcrystals hosting silicon vacancy centers may enable unprecedented force sensitivity and gravitational measurements in a tabletop experiment with macroscopic quantum superposition states.