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Greetings!

Bob McElrath <bob+maxima@mcelrath.org> writes:

*> Bertfried Fauser [fauser@spock.physik.uni-konstanz.de] wrote:
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*> >
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*> > Hi,
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*> >
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*> > as fare as I understand the package (havn't though done much with it, so I
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*> > might be wrong), it is designed for very "practical" purpose (ie
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*> > phenomenology.) Many problems can be subsummarized in a larger frame of
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*> > mathematics. Given the type system of AXIOM, it would be, in my eyes, a
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*> > fraud to implement something like "Dirac matrixes" and trace rules, while
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*> > this is a closed structure in a *-autonomous category. However, I am still
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*> > not able myself to give AXIOM code for such a vast general thing.
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*>
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*> The *purpose* of FeynCalc is to be a general purpose framework for doing
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*> quantum field theory calculations. That is, dirac matrices, trace
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*> rules, Feynman rules from Lagrangians, representations for fields and
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*> the like.
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*>
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*> It also contains code for doing one-loop integrals. This same code
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*> exists in several places (I know of a fortan library "ff" and a Maple
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*> package "xloops" as well), and I can point to the papers if people
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

I think this would be helpful.

Take care,

*> desire. But the loop code is only half of FeynCalc.
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*>
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*> The actual algorithms are straightforward, but very tedious to
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*> calculate, so thus the results are collected into libraries like
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*> FeynCalc. There are yet a handful of obstacles in dealing with
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*> divergences that have kept us from writing a fully automatic method of
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*> computing these loop integrals. At one loop I think it can be fully
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*> automatic, but I do not think this is something a non-expert would want
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*> to tackle.
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*>
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*> The "algorithms" are documented in QFT textbooks such as Peskin &
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*> Schroeder "An Introduction to Quantum Field Theory", Weinberg "Quantum
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*> Theory of Fields", etc. This is a one-year graduate level physics
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*> course. The decomposition of loop integrals into scalar integrals was
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*> done by Passarino and Veltman
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*> http://dx.doi.org/10.1016/0550-3213(79)90234-7
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*> though these days it's not the only way...
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*>
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*> Cheers,
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*> Bob McElrath [Univ. of California at Davis, Department of Physics]
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*>
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*> "A great many people think they are thinking when they are merely
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*> rearranging their prejudices." -- William James
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*>
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-- Camm Maguire camm@enhanced.com ========================================================================== "The earth is but one country, and mankind its citizens." -- Baha'u'llah

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