Question
Verify that the Dirac equation follows from$$\mathcal{L}=i \bar{\psi} \gamma_{\bar{\mu}} \partial^{\mu} \psi-m \bar{\psi} \psi,$$where each of the four components of $\psi$ and $\bar{\psi}$ is regarded as an independent field variable.
Step 1
First, we need to find the Euler-Lagrange equations for the Lagrangian density given above. The Euler-Lagrange equations for a field theory are given by: $$ \frac{\partial \mathcal{L}}{\partial \psi} - \partial_\mu \left(\frac{\partial Show more…
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