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Hi Kasper,

How can I tell cadabra2 about the \gamma{5} matrix? If I declare it to be ::GammaMatrix, then it mixes with the other \gamma{\mu} when I run joingamma() and sortspinors().


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1 Answer

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If you're working on four dimensions, $\gamma^5$ is proportional to the product of the four (elemental) gamma's. Therefore you can define something like

\delta_{m n}::KroneckerDelta;

g5 := e_{l m n p} \Gamma^{l m n p};

You have to normalise this definition accordingly.

Remember that Cadabra has a definition for the imaginary number

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