Ensuring Clean Quantum Measurements in the Stern-Gerlach Experiment

[sokrates]

Spin Precession Revisited

Abstract: The passage of a spin-1/2neutral particle through a region of *uniform magnetic field* and the corresponding precession mechanism is analyzed from the viewpoint of scattering theory, with particular consideration of the role of the field boundaries.

I hope they have also treated the SG setup here... OR did you just google this without really looking?

 

[transience]

The way I understand it is that the Stern-Gerlach experiment is a measurement device that splits the beam according to the projection of the spin component on the z-axis.

The quantum state of whatever makes up the beam isn't pure, meaning that the the z component of the spin can be expressed in terms of spins along the x or y axis, because of this it doesn't matter how you rotate the magnets you will still see the splitting.