# Program for Traces of Dirac matrices

1. Dec 5, 2009

### PJK

Hi all,

I want to calculate traces of Dirac matrices with a program like Mathematica.
I found the package FeynCalc but it seems to be outdated.
It is always producing results like this:
Code (Text):

4 (-(DiracCanonical->False) (Factoring->False) (FeynCalcInternal->True) g^(mu nu)

(InsideDiracTrace->True) k\[CenterDot]l-l^2 (DiracCanonical->False) (Factoring->False)

(FeynCalcInternal->True) g^(mu nu) (InsideDiracTrace->True)+m^2

(DiracCanonical->False) (Factoring->False) (FeynCalcInternal->True) g^(mu nu)

(InsideDiracTrace->True)+k^nu l^mu (DiracCanonical->False) (Factoring->False)

(FeynCalcInternal->True) (InsideDiracTrace->True)+k^mu l^nu (DiracCanonical->False)

(Factoring->False) (FeynCalcInternal->True) (InsideDiracTrace->True)+2 l^mu l^nu

(DiracCanonical->False) (Factoring->False) (FeynCalcInternal->True)

(InsideDiracTrace->True))
Which is quite annoying. Even worse I want to use the metric (-1,1,1,1) and there seems to be no support for changing the metric.
Is there a better program/package for doing those calculations?

2. Oct 23, 2010

### LanceV

Apparently this was a difficult question. But maybe one year later someone has got an idea?
I have the same problem as the one described above.

3. Oct 23, 2010

### comote

I am not too(edit: At all) familiar with the Dirac matrices but following the discussion on

http://mathworld.wolfram.com/DiracMatrices.html

What is wrong with using $Tr(A\otimes B) = Tr(A)Tr(B)$?

4. Oct 23, 2010

### LanceV

Thanks for your input. Of course it would be possible to implement all the Dirac algebra using the functions of Mathematica. That's what the people of FeynCalc did. But since it has already been done, I would rather use it, instead of redoing it myself. And FeynCalc DOES work; its output is just unreadable (as can be seen in the example above).

5. Oct 24, 2010

### maverick280857

Last edited by a moderator: May 5, 2017