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Question: physics - problem with multiplying Dirac gamma matrices

Question:physics - problem with multiplying Dirac gamma matrices

larry stead 45 Maple
physics
October 23 2019
2

I am trying to do matrix multiplication with Dirac gamma matrices, but am getting a recursion error. 

the final input line, which is causing the error, doesn't seem to be inserted, but it is:

Library:-PerformMatrixOperations((mt . (Dgamma[2])) . m)

can anybody tell me what i'm doing wrong? i don't understand why 

Dgamma[2] . m 

works but 

mw . Dgamma[2] . m 

gets the recursion error. 

then i saw something that made me think i needed to use 'matrix', instead of 'Matrix'. so i tried that(gamult2) - now the 2nd multiply works, and the first fails.

any help greatly appreciated!

thanks,

larry

restart

with(Physics)

Physics:-Version()

`The "Physics Updates" version in the MapleCloud is 452 and is the same as the version installed in this computer, created 2019, October 23, 13:26 hours, found in the directory /Users/lstead/maple/toolbox/2019/Physics Updates/lib/`

 (1)

with(LinearAlgebra)

``

m := Matrix(4, 1, {(1, 1) = 1, (2, 1) = 2, (3, 1) = 3, (4, 1) = 4})

Matrix(%id = 18446744078528784254)

 (2)

mt := Transpose(m)

Matrix(%id = 18446744078392267830)

 (3)

mt.m

Matrix(%id = 18446744078392260238)

 (4)

Library:-PerformMatrixOperations(Dgamma[2].m)

Matrix(%id = 18446744078528770526)

 (5)

Library:-PerformMatrixOperations(mt.Dgamma[2].m)

Error, (in Physics:-GetDefineINFO) too many levels of recursion

  

``


 

Download gammult.mw

gammult2.mw
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