Name: Vladyslav Shtabovenko Date: 10/21/17-07:20:05 AM Z
> Dear Prffesior,
> I am a research-fellow at a physics institute of India,
> working on “Finite Temperature Field Theory”,and “QGP
phenomenology”.
> I am trying to use Feyncalc for my calculations but facing some
problems.
> Let me explain them.
> At finite temperature the propagators and the vertices
> loses the simple Lorentz invariant structure and acquires an
admixture
> of both spatial and temporal components. Therefore, to perform
these
> calculations the programe should be able to recognige both the
zeroth
> and spatial components of a four-vector and know should be able to
do
> calculations with DiracGamma[0] and
Diracgamma[i],i=1,2,3 explicitly.
> Can such things be done with feynCalc? Plese let me know.
> Sincerly
>
> Purnendu
More than 16 years after the original question, the answer is yes, with FeynCalc 9.3 (aka the current development version) this will be possible.
For example (TGA[] is gamma^0, CGA[i] is gamma^i)
Tr[CGA[i].CGA[j]] (i.e. the trace of two Dirac matrices with Cartesian indices)
yields
-4 CartesianPair[CartesianIndex[i], CartesianIndex[j]]
where CartesianPair[CartesianIndex[i], CartesianIndex[j]] signifies a Kronecker delta
Then
DiracSimplify[TGA[].TGA[]]
yields 1, since gamma^0 gamma^0 =1, while
DiracSimplify[CGA[i, j, i, j]] (i.e. g^i g^j g^i g^j
gives -3
This still needs some testing, performance improvements and a proper
documentation,
but this is a work in progress to be completed soon.
Cheers,
Vladyslav