Can You Help Me Couple 3 Spin 1/2 Particles?

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SUMMARY

The discussion focuses on the coupling of three spin 1/2 particles, specifically addressing the calculation of Clebsch-Gordan (C-G) coefficients. The user initially attempts to compute the coefficients using the C-G table but encounters an error in their second calculation. A correction is provided, stating that adding angular momentum L=0 to any state results in a C-G coefficient of 1. The correct coefficient for the coupling of the specified states is confirmed to be 1/√2.

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  • Understanding of Clebsch-Gordan coefficients
  • Familiarity with angular momentum in quantum mechanics
  • Knowledge of quantum state notation and coupling schemes
  • Basic proficiency in Quantum Mechanics concepts
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  • Study the derivation of Clebsch-Gordan coefficients in detail
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Quantum physicists, students of quantum mechanics, and anyone involved in the study of angular momentum coupling in particle physics will benefit from this discussion.

JoJoQuinoa
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Hello,

I'm trying to couple 3 spin 1/2 particles. So far, I have been able to find the coefficient for the other states but I can't get the results for ##j_{12} = 0## to ##j_3=1/2##.
Here is my attempt:
1) Using CG table ##<j_1;j_2;m_1;m_2|J;M><\frac{1}{2};\frac{1}{2};-\frac{1}{2};\frac{1}{2}|0;0> = 1/\sqrt2##
2) Using CG table again with ##\frac{1}{\sqrt2}<0;\frac{1}{2};0;\frac{1}{2}|\frac{1}{2};\frac{1}{2}> = 1/\sqrt2*1/\sqrt3 = 1/\sqrt6##

The correct answer is ##1/\sqrt2##.

Please help!

Thank you
 
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Your second C-G is wrong. Adding L=0 to anything has C-G=1.
 
Meir Achuz said:
Your second C-G is wrong. Adding L=0 to anything has C-G=1.
Hi Meir Achuz,

Thank you for your reply. Do you mind explaining a little bit in details or direct me to where I can find more info on that? The sources I've looked at only listed the results so I guess this is supposed to be known? I'm using Quantum Mechanics by David H. McIntyre.
 

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