Dirac Gamma matrices in the (-+++) metric

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Discussion Overview

The discussion centers on the representation of Dirac gamma matrices in the (-+++) metric, contrasting it with the more common +--- metric. Participants seek references and clarification on the differences in conventions used in various texts.

Discussion Character

  • Technical explanation
  • Debate/contested

Main Points Raised

  • Thomas Brennan inquires about a representation of the Dirac gamma matrices suitable for the (-+++) metric, noting the typical representation for the +--- metric.
  • Some participants suggest looking at specific texts, such as "Tools for Supersymmetry" by Van Proeyen and "Supersymmetry and Gauge Theory" by Lambert.
  • Another participant mentions that Weinberg's "Quantum Theory of Fields, vol. I" uses the (-+++) signature and provides a representation of the Dirac matrices.
  • There is a request for clarification on the full title of Weinberg's book, which is confirmed by another participant.
  • Participants note that Srednicki's text also includes gamma matrices in the (-+++) signature, but there is uncertainty regarding the differences in conventions compared to Weinberg's.
  • One participant speculates that Srednicki's gamma matrices may align with the inquiry but highlights a potential difference in the sign of the anticommutator relation.

Areas of Agreement / Disagreement

Participants generally agree on the existence of representations for the (-+++) metric in specific texts, but there are differing views on the conventions used in those texts, leading to some uncertainty.

Contextual Notes

There are unresolved questions regarding the specific conventions and potential discrepancies between the representations in different texts, particularly between Weinberg's and Srednicki's approaches.

brennan_t
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Hi,

The typical representation of the Dirac gamma matrices are designed for the +--- metric. For example

/gamma^0 = [1 & 0 \\ 0 & -1] , /gamma^i = [0 & /sigma^i \\ - /sigma^i & 0]

this corresponds to the metric +---

Does anyone know a representation of the gamma matrices for -+++?

Can you refer me to a published article or text?

Thank you!

Thomas Brennan
Research Assistant Professor
West Virginia Wesleyan College.
 
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Look for instance at "Tools for supersymmetry" by Van Proeyen, or "Supersymmetry and Gauge theory" by Lambert.
 
Weinberg, vol I uses the (-+++) signature, and gives a representation of the Dirac matrices on p.216.
 
Bill_K:

Thanks, what is the rest of the title? Steven Weinberg has written several books...

Is it the 'Quantum Theory of Fields, vol. I"

I think I answered my own question. Thanks.
 
Last edited:
Yes, that's the book.

Srednicki's text (downloadable from his web page) also has gamma matrices in (-+++) signature. But IIRC his conventions are not the same as Weinberg's.
 
Yes, that's the book.

Srednicki's text (downloadable from his web page) also has gamma matrices in (-+++) signature. But IIRC his conventions are not the same as Weinberg's.

Actually I think Srednicki's gamma matrices are the same as yours. But he puts an extra minus sign on the RHS of the anticommutator:

\{\gamma^\mu,\gamma^\nu\}=-2\eta^{\mu\nu}
 

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