The Bloch sphere helps understanding the mathematical results for a one-spin state. One could think of the state as a spin pointing in direction [itex]\hat{n}[/itex]. Then the probability for measureing the spin in the direction [itex]\hat{m}[/itex] is simply(adsbygoogle = window.adsbygoogle || []).push({});

[tex]

P=|<\hat{m}|\hat{n}>|^2=\frac{1+\hat{n}\cdot\hat{m}}{2}

[/tex]

and that's all one need to know for one spin.

But what about multiple spins? How can I use a similar "Bloch-coordinate system" for more spins? In a way one only needs to know the scalar product? I came up with an expression but it's still quite complex.

Does any know an easier treatment of multiple spins but in terms of these "Bloch-coordinates"?

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# Bloch sphere model for many spins?

Can you offer guidance or do you also need help?

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