Proving an Identity Involving Gamma Matrices: Help Needed

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Discussion Overview

The discussion revolves around proving an identity involving gamma matrices, specifically the transposition of gamma matrices and its relation to charge conjugation. Participants explore various approaches to establish this identity, including representation dependence and the use of anticommutation relations.

Discussion Character

  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant seeks help in proving the identity (\gamma ^{\mu})^T = \gamma ^0 \gamma ^{\mu} \gamma ^0, expressing uncertainty about the invariance under unitary transformations.
  • Another participant suggests that the identity to prove might actually be (\gamma^{\mu})^{\dagger}=\gamma^0 \gamma^{\mu} \gamma^0, providing a reference for further reading.
  • A different participant mentions several forms of matrices related to gamma matrices, indicating that while they can be expressed in specific representations, they may not hold across different representations.
  • One participant clarifies that they need the proof for the transposed version, asserting that the dagger version is representation independent, while expressing uncertainty about the transposed version's independence.
  • Another participant advises starting with the anticommutation relations of gamma matrices and considering the properties of \gamma^0 in different representations to approach the proof.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the identity in question, with multiple competing views regarding the representation dependence of the transposed and dagger forms of the gamma matrices.

Contextual Notes

Participants express uncertainty about the representation dependence of the transposed identity and the implications of different representations on the properties of gamma matrices.

LayMuon
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Can anyone help me in proving the following identity:

<br /> <br /> (\gamma ^{\mu} )^T = \gamma ^0 \gamma ^{\mu} \gamma ^0<br /> <br />

I understand that one can proceed by proving it say in standard representation and then proving that it's invariant under unitary transformations. this last thing is the one that I am not able to prove.

Are there other ways to go?

Thanks.
 
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LayMuon, There are several matrices like the one you're seeking:

μA-1 = - (γμ)
μB-1 = (γμ)~
μC-1 = (γμ)*

and so on. You can express each of them as a specific product of gamma matrices in the standard representation, or any other given representation, but it will not hold when you go from one representation to another. Generally we just treat them as an independent matrix and let it go at that without trying to write them in terms of the gammas.
 


vanhees71 said:
I think you rather want to prove
(\gamma^{\mu})^{\dagger}=\gamma^0 \gamma^{\mu} \gamma^0.
For an intro to the Dirac equation and all that, see

http://fias.uni-frankfurt.de/~hees/publ/off-eq-qft.pdf

No, I can prove the one with dagger, I need the proof for the transposed version. Bill is saying it's representation dependent. Dagger version is not, I am not sure about the transposed version. Judging from my textbook it should be representation independent too.
 


Bill, this post is a follow-up of my previous one, I need this identity to prove the charge conjugation relation in my way. I had a look at the equations you brought in Bjorken and Drell.
 


you should better start with the anticommutation relation followed by gamma matrices and treat γ0 as a single case when μ=0 and how the hermitian conjugate of different gamma matrices is defined.Like γ0 is hermitian in one representation then it's hermitian conjugate is γ0 itself but in other representation it may not be but the relation will prove the consequence.
 

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