  We demonstrate a new mechanical transduction platform for individual spin
qubits. In our approach, single micro-magnets are trapped using a type-II
superconductor in proximity of spin qubits, enabling direct magnetic coupling
between the two systems. Controlling the distance between the magnet and the
superconductor during cooldown, we demonstrate three dimensional trapping with
quality factors around one million and kHz trapping frequencies. We further
exploit the large magnetic moment to mass ratio of this mechanical oscillator
to couple its motion to the spin degree of freedom of an individual nitrogen
vacancy center in diamond. Our approach provides a new path towards interfacing
individual spin qubits with mechanical motion for testing quantum mechanics
with mesoscopic objects, realization of quantum networks, and ultra-sensitive
metrology.
