I have read texts about it, but I still haven't understood what the steps are. Every author seems to speak about it in a different way or order. What are the steps of adding two spins? Where I can find a correct demonstration?

  • $\begingroup$ If you are reading standard quantum mechanics textbooks whose authors are Griffith, or Sakurai, or Shankar, although the content about addition of spin angular momentum may be stated in a different way, they are mathematically equivalent. $\endgroup$
    – Andy Chen
    Aug 6 at 12:29
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    $\begingroup$ Unless you can pinpoint an issue with a specific step, any answer will just repeat what’s in a textbook. $\endgroup$ Aug 6 at 12:29
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    $\begingroup$ However, in my opinion, Griffith's version is a little bit too introductory, and can be confusing in the section about CG coefficients. Sakurai and Shankar's versions give you a more general picture about how addition of two spins are done. $\endgroup$
    – Andy Chen
    Aug 6 at 12:32
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    $\begingroup$ Please clarify your specific problem or provide additional details to highlight exactly what you need. As it's currently written, it's hard to tell exactly what you're asking. $\endgroup$ Aug 6 at 12:38
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    $\begingroup$ It may also be a good idea to learn some group theory and irreducible representations of $\text{SU}(2)$ and $\text{SO}(3)$, these topics ultimately give you complete understanding about complex topics of angular momentum including the Wigner Eckart theorem. $\endgroup$
    – Andy Chen
    Aug 6 at 12:40


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