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Does a FeynCalc command exist, that simplifies the expression

GA[a].GA[b]+GA[b].GA[a]

to

2 MT[a,b]

I've tried Calc, DiracSimplify and DiracTrick to no avail.

If not, how can I do it with vanilla Mathematica?

edit for clarification purposes.

GA[mu] refers to the GammaMatrices (https://en.wikipedia.org/wiki/Gamma_matrices). There exists an anticommutator relation that allows the anticommuter of two GammaMatrices with Minkowksi indices $\mu$ and $\nu$ to be simplified to the metric tensor element $\eta^{\mu\nu}$.

$\{\gamma^\mu, \gamma^\nu\} = \gamma^\mu\gamma^\nu+\gamma^\nu\gamma^\mu = 2\eta^{\mu\nu}$

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  • $\begingroup$ Why the downvote? $\endgroup$ Apr 26 '19 at 11:09
  • 2
    $\begingroup$ You need to use DiracOrder or DiracSimplify with the option DiracCanonical set to True. $\endgroup$
    – vsht
    Apr 26 '19 at 11:51
  • $\begingroup$ You should post this as an answer as it is correct. $\endgroup$ Apr 26 '19 at 11:59

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