Gauge invariance and the degrees of freedom
125565
Counting the number of propagating degrees of freedom in Lorenz Gauge Electrodynamics
86967
The concept of particle in QFT
69389
Gauge fields and strings: Loop equations
147524
Why is the "canonical momentum" for the Dirac equation not defined in terms of the "gauge covariant derivative"?
80596
Ambiguities in the energy-momentum tensor
34788
Lagrangian for relativistic massless point particle
135071
Energy momentum tensor from Noether's theorem
136143
Are gauge choices in electrodynamics really always possible?
121584
Rigor in quantum field theory
88491
Holonomic constraints and degrees of freedom
105660
Invariance of action $\Rightarrow$ covariance of field equations?
26125
Does the canonical commutation relation fix the form of the momentum operator?
29152
Conversion of the Polyakov action into the Nambo-Goto action?
55316
Why is the Yang-Mills gauge group assumed compact and semi-simple?
113610
Spinor field normalisation from poles in the propagator
1330
Fermions, different species and (anti-)commutation rules
56911
Proving invariance of $ds^2$ from the invariance of the speed of light