Because the spinning electron has electrical charge, it acts like a tiny magnet. Ultimately the magnetic properties of all materials, down to the tackiest refrigerator magnet, arise from the magnetism of their electrons. The Ames team began by finding separable degrees of freedom in the motion of the electron. The electron has two degrees of freedom, they explain. One is the location of the electron in space, and the other is its spin.
Electrons move fast, so the coordinate degree of freedom is a fast degree of freedom.
But the orientation of a spinning electron changes only slowly, and so the spin degree of freedom is slow. Because of this difference in time scale, the team thought the complete quantum equation for the electron could be divided into two components, one describing the motion of the electron in space and the other describing the motion of the electron's spin axis. So they rolled up their sleeves and sat down to work. The equation for the spin axis determines the orientation of the electron's magnetic moment, and the wave function determines the magnitude of the electron's magnetic moment. Together, these coupled classical and quantum mechanical equations of motion capture the spin dynamics of the electron in a solvable form.