Talk:Wigner-Eckart theorem

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Help with this template Comments: edit – history – watch – refresh In physics the 'k' conventionally refers to the rank of the tensor and 'q' to the component. Both Sakurai (Modern Quantum Mech) and Messiah (Quantum Mechanics, vol II) place the k in the upper index and q lower. Shankar (Principles of Quantum) switches the index placement (k - rank, on bottom; q - component, on top). So, either index placement should be ok, but its probably not a good idea to differ from the conventional letters used. Rephorm (talk) 15:22, 15 February 2008 (UTC)

I think we need an article about the Wigner-Eckart theorem!

Here are some links: Link 1 Link 2

-spiralhighway

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it reads "where (T) is a rank q spherical tensor", shouldn't it be a rank k spherical tensor?

---> According to the reference article: http://galileo.phys.virginia.edu/classes/752.mf1i.spring03/TensorOperators.htm

    the subscript is the rank and superscript is the component. It looks like the example was worked out wrong, so I corrected it
    bphillab 14:33, 21 January 2007 (UTC)

Sorry, no. The rank is the superscript. is rank k, component q. Looking at the CG coefficient, it'd have to be that way; k is analogous to j, and q is analogous to m. Therefore k is the one that determines the overall properties (the rank) and q is less important. JFlav (talk) 05:35, 27 February 2008 (UTC)