Dirac field
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In physics, a Dirac field, named after Paul Dirac, is a fermionic field (usually a quantized field, as usual in quantum field theory) associated with spin 1/2 fermions such as the electron or muon.
The Dirac field transforms as the unconstrained spinor, and it satisfies the Dirac equation. The usual free Lagrangian for the Dirac field is
- <math>{\mathcal L} = \bar\Psi (i\partial_\mu \gamma^\mu - m)\Psi.\,</math>
The Dirac fields are important components of quantum electrodynamics and the standard model.
A Dirac field is equivalent to two Majorana fields with the same mass. A massless Dirac field is equivalent to two (massless) Weyl fields.