Introduction of the vector potential $A_{\mu}$ for the local gauge invariance of the complex scalar field lagrangian
10785
Form of the Classical EM Lagrangian
138908
Most general Lagrangian in CFT in 0+1D
112187
Is there a way to see that $ \nabla_\mu g_{\nu \rho} = 0 $ without explicit computation, where $\nabla_\mu$ refers to the covariant derivative?
104604
How do I find the values for the structure constants ($f^{abc}$) of a gauge group?
48930
Least-action classical electrodynamics without potentials
16293
N-dimensional generalization of vector curl from elements of Jacobian
153727
Constant term in Lagrangian
46053
How to find Hamiltonian from this simple Lagrangian? (tricky)
121830
The commutators of related vector fields are related
28946
Derivation of Spin Lagrangian
82135
Lagrangian to Hamiltonian in Quantum Field Theory
27866
Does existence of magnetic monopole break covariant form of Maxwell’s equations for potentials?
70880
Invariance of canonical Hamiltonian equation when adding the total time derivative of a function of $q_i$ and $t$ to the Lagrangian
44953
Gauge symmetries and elementary particles
87914
Contradictory result for scalar-field propagator from Feynman rules and LSZ formula
34788
Lagrangian for relativistic massless point particle
101944
Fundamental invariants of the electromagnetic field