On Nov. 17, Feifei Li wrote
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I am a postdoc in physics at Northwestern University.
Recently I started using Maxima in research
and got amazed how powerful it is as an free
software. I also find the tutorial you post on
your website the most helpful one.
Thanks a lot for creating these materials!
I am writing to you because I have a question
about how to calculate commutators with Maxima.
I need to calculate some commutators
between epxressions that are polynomial in spin operators.
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I am attaching two files:
1. pauli.mac, which should be loaded in
before running
2. the batch file: paulidem.mac
The run of the batch file is shown in a comment at
the end.
This will show you one way to work
with explicit matrices, here the Pauli matrices,
and prove all the properties in terms of the
kronecker delta (kron_delta(i,j) in Maxima,
and the completely antisymmetric 3d tensor
eps3[i,j,k] defined in pauli.mac.
I use both a definition of the commutator (comm)
and the anticommutator (acomm) near the end.
Note also conj = homemade compex conjugate
and hc = hermitian conjugate .
I will post both these files to my webpage
tomorrow, in case they might be generally
helpful.
Hope this helps,
Ted Woollett
http://www.csulb.edu/~woollett
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