How is the spin of a wave packet determined?

Answer 1

Spin arises out of the inclusion of special relativity into the time dependent Schroedinger equation. The wavefunction then becomes a spinor rather than a scalar (a spinor is a vector with specific properties under rotation groups).

Answer 2

Spin refers to the angular momentum intrinsic to an elementary particle, and can be inferred from experiments. For example, for electrons, physicists use a magnetic field, which acts upon the electron's intrinsic magnetic dipole moment. The result is that the spin vector undergoes precession, just like a classical gyroscope. Particles with spin can possess a magnetic dipole moment, just like a rotating electrically charged body in classical electrodynamics. These magnetic moments can be experimentally observed in several ways, e.g. by the deflection of particles by inhomogeneous magnetic fields, or by measuring the magnetic fields generated by the particles themselves.

PS - all sub-atomic particles can be described as a wave pcket. Also, the method to meansure the spin of photons would be completely different from that of an electron as described above. For photons, the spin can be determined by measuring the polarization of the light (i.. you would use polarized filters like those in polarized sunglasses).

Answer 3

r u obssessed with wave packets? uve asked atleast 4 questions abt them in 2 days...according to me, wave packets do not have a spin quantum number...its a probablity wave, a purely theoritical concept