SU(2) GAUGE-SYMMETRY OF A NONRELATIVISTIC SPIN 1/2 PARTICLE

Abstract

A non-relativistic quantum mechanical theory for a spin magnetic moment is constructed by quantizing the classical Hamiltonian based on the classical model of a magnetic moment as a localized current. It is shown that the electromagnetic interaction of a spin magnetic moment can be described by SU(2) gauge fields. It is argued that the quantum mechanical force is not gauge invariant and its classical limit can be obtained only at a fixed gauge.