Name: Vladyslav Shtabovenko Date: 05/12/14-10:08:04 AM Z
Hi,
> Before we load Feyncalc and Feynarts, all is ok:
>
Conjugate[Exp[i*Pi/4]]=Exp-i*Pi/4,
> but when the packages(Feyncalc and Feynarts) are both loaded, I
find
this BUG appear:
>
Conjugate[Exp[i*Pi/4]]=Expi*Pi/4.
> when I set $LoadPhi=False and $LoadFeynArts=False
> and execute <<HighEnergyPhysics`FeynCalc`,this time I only
load
FeynCalc, I find this BUG disappear again:
>
Conjugate[Exp[i*Pi/4]]=Exp-i*Pi/4.
The problem is that in the present state (at least in Mathematica 9)
FeynArts and Phi don’t really work with FeynCalc. When you load them
nevertheless, you get a bunch of error messages related to shadowing.
As you correctly observed, using
$LoadPhi=False
$LoadFeynArts=False
<<HighEnergyPhysics`FeynCalc`
avoids these problems.
> Another question is:
> when use “ComplexConjugate” to replace “Conjugate” I find another
question.
>
ComplexConjugate[Exp[i*Pi/4]]=Exp-i*Pi/4
> ComplexConjugate[5^i]=5^i(BUG?)
> please contact me soon!
>
Email:[qfsun_at_HIDDEN-E-MAIL]
> Thank you!
>
I think that this behavior of ComplexConjugate is not a bug. The
description of the command (?ComplexConjugate) says
-——————————————————–
ComplexConjugate[expr] complex conjugates expr.
It operates on Fermion-lines, i.e., products
of Spinor[..] .DiracMatrix[..] . Spinor[..].
For taking the spin sum (i.e. constructing the traces) use
FermionSpinSum.
WARNING: In expr should be NO explicit I in denominators!
-——————————————————–
Now if you apply ComplexConjugate to 5^I, you are explicitly
ignoring the warning, which is why you are getting a wrong result.
I would not use ComplexConjugate for anything that is not a fermion
line
or contains explicit I’s.
Cheers,
Vladyslav