File talk:Bell test for entangled qubits.svg

Spin ½

Your should use the Bloch sphere (i.e. Riemann sphere a.k.a. CP¹) to illustrate the geometry of spin ½, not the state vector projection as in this illustrations. The thing which you represent as a 45° turn, the transform:

${\frac {1}{\sqrt {2}}}\cdot {\begin{bmatrix}1&-1\\1&1\end{bmatrix}}$

corresponds to physical rotation to 90° in the case of spin ½. Indeed, this illustration has correct geometrical connotation for massless spin 1, such as photons. Incnis Mrsi (talk) 10:59, 19 February 2011 (UTC)