- #1

- 199

- 11

I say this because the operator [tex]\hat{S}_z\otimes \hat{I}[/tex] has eigenvectors (like [tex]\frac{1}{\sqrt{2}}(\uparrow\otimes\uparrow + \uparrow\otimes\downarrow )[/tex]) which (1) would give Alice the spin up result and (2) have a nonzero inner product with the initial (singlet) state. So why can't the state collapse to another eigenvector like the one I just mentioned (and thus Bob not necessarily measure spin down)? I think I'm missing something simple here.