In summary, the Dirac Lagrangian has an equation of motion that is either the Dirac equation or a [overline]Ψ[\\overline] version of the Dirac equation.
The first two equations of motion say that ∂L/∂[overline]Ψ[\\overline]=-[overline]Ψ[\\overline]m and ∂L/∂Ψ=i[overline]Ψ[\\overline]γμ.
Oct 3, 2022.
Dirac Equation Formula
=(x,t) is the electron wave function.
M is the electron mass at rest.
X, t is the spacetime coordinates. p1, p2, p3 are the momentum components.
One motivation for the development of the Lagrangian formalism on fields, and more generally, for classical field theory, is to provide a clean mathematical foundation for quantum field theory, which is infamously beset by formal difficulties that make it unacceptable as a mathematical theory.