(c) Dr Paul Kinsler. [Acknowledgements & Feedback]
This is part of an information maze -- see the index-file for the full picture.
Quantum spin is an intrinsic property of some particles. It behaves exactly like angular-momentum, and has the same units, but is not caused by the rotation of the particle - it is just "there". It occurs in integer multiples of Plancks-constant divided by 2pi.
Most of the elementary-particles have a non-zero spin. Most types of particles have half-integral spin (e.g. electrons, protons, neutrons with +1/2 or -1/2), and are known as fermions; but others have integral spin (e.g. photons with +1 or -1), and are known as bosons.
Spin adds up - the spin of an atomic nucleus is just the sum of all the spins of its constituent particles.
XINDEX: quantum-mechanic, quantum-computer, proton, photon, neutron, light, fermion, electron, boson, index-file.
19990610 (c) Paul Kinsler
XKEYWORD: spin
Email Feedback: Dr.Paul.Kinsler@physics.org
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