Question

#Quantum mechanics:
Why particles only in same eigenstate can interfere?

Answer 1

In double slit experiment if "Stern-Gerlach" apparatus attached to the slits in such a manner that only electrones with\[ s_z =\hbar/2\] can pass through A and only electrons with \[s_z = -\hbar/2\] can pass through B. What will be the intensity pattern on the screen.
Answer:\[I=I_A(x) +I_B (x)\] +no interference term(why?).