Local Gauge Invariance and Masslessness
30745
Why can't photons have a mass?
101944
Fundamental invariants of the electromagnetic field
55316
Why is the Yang-Mills gauge group assumed compact and semi-simple?
11181
Counting degrees of freedom of gauge bosons
76255
Does a gluon have mass or not?
95125
Rest mass of the photon
120490
Does magnetic monopole violate $U(1)$ gauge symmetry?
24547
Steps for going from Polyakov action to low-energy effective action (SUGRA?) in String Theory
82135
Lagrangian to Hamiltonian in Quantum Field Theory
145003
How can a point-like particle "feel" gravity, if locally the curvature of spacetime is always flat?
106506
How to derive completeness relation in quantum field theory with a Lorentz invariant measure?
135071
Energy momentum tensor from Noether's theorem
38673
General relativity: For massless particles, is the momentum and velocity 4-vectors equal?
150344
Basis of the null space
157882
Why are gluons believed to be massless?
69389
Gauge fields and strings: Loop equations
92532
Conservation of Mass during Electron - Positron Annihilation