Date: 02/01/16-03:00:36 PM Z

Hi,

I'm afraid that there is no straight-forward way to change the sign of
the anticommutation relation everywhere. The reason is that in most
cases FeynCalc doesn't apply the anticommutation relation directly, but
rather uses known formulas to simplify different chains of Dirac
matrices (see e.g. Veltman's Gammatrica).

To have DiracSimplify and DiracTrace work with Euclidean matrices with
any reasonable performance, one would need to rederive all those
formulas with the different metric (which possibly someone has already
did) and reimplement them again. This is of course not impossible, but
would reqire quite some work and testing.

You can always do some tricks to make FeynCalc work in your way, e.g.
multiplying each Dirac matrix with an I to have {i g^mu, i g^nu} = - 2
eta^munu, but then you still need to be very careful with Gamma 5 and
the Levi-Civita tensor.

Cheers,

Am 26.01.2016 um 02:27 schrieb Naser Ahmadiniaz:
> Hi,
>
> I am using FeynCalc package in Mathematica to calculate some complicated Traces, but I think the default convention for the anticommutator of two Gamma matrices in this package is with positive a sign on the right-hand side as
>
> ${\gamma^\mu,\gamma^\nu}=+2\eta^{\mu\nu}$
>
> I would like to change this convention to the one with a negative sign, i.e
>
> ${\gamma^\mu,\gamma^\nu}=-2\eta^{\mu\nu}$
>
> how can I do that once for all?
>
> Thanks,
> Naser
>

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