In &5.6 writes:(adsbygoogle = window.adsbygoogle || []).push({});

"An (A,A) field (A is spin) contains terms with only integer spins 2A,2A-1,...,0, and corresponds to a traceless symmetric tensor of rank 2A.(Note that the number of independent components of a symmetric tensor of rank 2A in four(space-time) dimensions is:

{4.5...(4+2A-1)}/(2A)!=(3+2A)!/6(2A)!

and the tracelessness condition reduces this to:

{(3+2A)!/6(2A)!}-{(1+2A)!/6(2A-2)!}=(2A+1)^2

as expected for an (A,A) field"

I can not derive the number of components of a tensor of rank 2A in four dimensions is

4.5...(4+2A-1) and the number of tracelessnes conditions is (1+2A)!/6(2A-2)!

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# A question in Weinberg's QFT

**Physics Forums | Science Articles, Homework Help, Discussion**