Name: Vladyslav Shtabovenko Date: 04/08/15-04:49:54 PM Z
The bug if now fixed in the repository
<https://github.com/FeynCalc/feyncalc/commit/1cc6a191ca358e106381851776b6ba433bda791b>
and
a =
DiracReduce[DiracMatrix[i].DiracMatrix[j].DiracMatrix[k]];
b =
DiracReduce[DiracMatrix[i].DiracMatrix[j].DiracMatrix[k]];
DiracSimplify[(SpinorUBar[p, m].a.SpinorU[p, m])
(SpinorUBar[k,
m].b.SpinorU[k, m])]
a =
DiracMatrix[i].DiracMatrix[j].DiracMatrix[k];
b =
DiracMatrix[i].DiracMatrix[j].DiracMatrix[k];
DiracReduce[(SpinorUBar[p, m].a.SpinorU[p, m])
(SpinorUBar[k,
m].b.SpinorU[k, m
return the same result. Thanks again!
Cheers,
Vladyslav
Am 01.04.2015 um 15:58 schrieb Vladyslav Shtabovenko:
> Hi Asher,
>
> thanks for reporting this. The problem comes from the index
renaming
> in DiracReduce, that doesn’t take into account that the double index
can
> already appear in the expression.
>
> We will fix this in the master repository very soon. For now, you
can
> either remove the line
>
> temp = Contract[temp, Rename-> True];
>
> in DiracReduce.m, or, if you are using the development version,
apply
> FCRenameDummyIndices on the results of DiracReduce:
>
> a =
DiracReduce[DiracMatrix[i].DiracMatrix[j].DiracMatrix[k]]
//
> FCRenameDummyIndices;
> b =
DiracReduce[DiracMatrix[i].DiracMatrix[j].DiracMatrix[k]]
//
> FCRenameDummyIndices;
> DiracSimplify[(SpinorUBar[p, m].a.SpinorU[p, m])
(SpinorUBar[k,
> m].b.SpinorU[k, m])]
>
> Sorry for the inconvenience.
>
> Cheers,
> Vladyslav
>
> Am 31.03.2015 um 00:55 schrieb Asher Berlin:
>> Hi,
>>
>> I’ve noticed that using DiracReduce on matrices before entering
them into expressions involving spinors results in errors in the final
evaluation. Consider the following input below:
>>
>> a =
DiracReduce[DiracMatrix[i].DiracMatrix[j].DiracMatrix[k]];
>> b =
DiracReduce[DiracMatrix[i].DiracMatrix[j].DiracMatrix[k]];
>> DiracSimplify[(SpinorUBar[p, m].a.SpinorU[p,
m])(SpinorUBar[k,m].b.SpinorU[k,m])]
>>
>> a =
DiracMatrix[i].DiracMatrix[j].DiracMatrix[k];
>> b =
DiracMatrix[i].DiracMatrix[j].DiracMatrix[k];
>> DiracReduce[(SpinorUBar[p, m].a.SpinorU[p,
m])(SpinorUBar[k,m].b.SpinorU[k,m])]
>>
>> You’ll notice that the 2 lines of output differ in one of the
terms. I’ve tried this using FC 8.2 and FC 9 and the same discrepancy
remains. Any ideas of what could be going wrong here?
>>