nLab spin

Redirected from "spins".
Contents

Context

Spin geometry

Quantum systems

quantum logic


quantum physics


quantum probability theoryobservables and states


quantum information


quantum computation

qbit

quantum algorithms:


quantum sensing


quantum communication

Contents

Idea

The spin of a particle in quantum mechanics/quantum field theory is its intrinsic angular momentum, but subject to the possibility that the particle may be a fermion so that that its angular momentum is not determined by the representation theory of the special orthogonal group, but of the spin group.

Properties

Spin-Statistics theorem

By the spin-statistics theorem, the spin of any elementary particle must be (in magnitude) half of an integer multiple of Planck's constant (=h/2π\hbar = h/2\pi), an integer if the particle is a boson but only a half-integer if the particle is a fermion.

References

The concept of intrinsic spin of the electron (making it a “spinor”) originates with:

  • Samuel A. Goudsmit, George E. Uhlenbeck: Ersetzung der Hypothese vom unmechanischen Zwang durch eine Forderung bezüglich des inneren Verhaltens jedes einzelnen Elektrons, Naturwissenschaften 13 47 (1925) 953 [pdf, pdf]

Historical recollection:

Last revised on October 22, 2023 at 13:03:19. See the history of this page for a list of all contributions to it.