The deviation of the path of a spinning particle from a circular geodesic in
the Schwarzschild spacetime is studied by an extension of the idea of geodesic
deviation. Within the Mathisson-Papapetrou-Dixon model and assuming the spin
parameter to be sufficiently small so that it makes sense to linearize the
equations of motion in the spin variables as well as in the geodesic deviation,
the spin-curvature force adds an additional driving term to the second order
system of linear ordinary differential equations satisfied by nearby geodesics.
Choosing initial conditions for geodesic motion leads to solutions for which
the deviations are entirely due to the spin-curvature force, and one finds that
the spinning particle position for a given fixed total spin oscillates roughly
within an ellipse in the plane perpendicular to the motion, while the azimuthal
motion undergoes similar oscillations plus an additional secular drift which
varies with spin orientation.Comment: 16 pages, 3 figures; published versio