  An experimental test at the intersection of quantum physics and general
relativity is proposed: measurement of relativistic frame dragging and geodetic
precession using intrinsic spin of electrons. The behavior of intrinsic spin in
spacetime dragged and warped by a massive rotating body is an experimentally
open question, hence the results of such a measurement could have important
theoretical consequences. Such a measurement is possible by using mm-scale
ferromagnetic gyroscopes in orbit around the Earth. Under conditions where the
rotational angular momentum of a ferromagnet is sufficiently small, a
ferromagnet's angular momentum is dominated by atomic electron spins and is
predicted to exhibit macroscopic gyroscopic behavior. If such a ferromagnetic
gyroscope is sufficiently isolated from the environment, rapid averaging of
quantum uncertainty via the spin-lattice interaction enables readout of the
ferromagnetic gyroscope dynamics with sufficient sensitivity to measure both
the Lense-Thirring (frame dragging) and de Sitter (geodetic precession) effects
due to the Earth.
