nLab
spin

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.

Revised on October 4, 2013 01:14:53 by Urs Schreiber (82.169.114.243)