Why must a fundamental particle's spin be a multiple of $\frac 1 2$?
1584
Why does spin have a discrete spectrum?
12422
Derivation of $E=pc$ for a massless particle?
41367
In what physical situation would the correlation of two spins be useful?
91849
Why in the relativistic quantum mechanics $ \gamma_4$ name is not used instead of $ \gamma_5$?
8241
Why doesn't the deuterium nucleus have spin $0$?
33187
Singlet and Triplet states: Why is the $S=0$ state defined as it is?
132834
Trying to understand relativistic action of a massive point particle
90221
Regarding the Weyl spinor and its transformation properties
132263
Pauli principle for particles very far apart from each other
70183
Angular Momentum Addition Theorem - Sanity Check
77245
Angular momentum squared and Hamiltonian?
44239
Why the extra term $\frac{1}{2}(\partial_{\rho}A^{\rho})^2$ in the photon Lagrangian?
147491
When is separating the total wavefunction into a space part and a spin part possible?
45802
Spacetime Torsion, the Spin tensor, and intrinsic spin in Einstein-Cartan theory
129289
What is the origin of the factor of $-1/4$ in the Maxwell Lagrangian?
113610
Spinor field normalisation from poles in the propagator
67588
Why does $|e^{ix}|^2 = 1$?