?Classical? equations of motion in quantum mechanics with gauge fields

Abstract

For the Schrodinger and Dirac equations in an external gauge field with symmetry groupSU(2), we construct to any degree of accuracy in powers ofh1/2,h→0, approximate dynamical states in the form of wave packets—semiclassical trajectory-coherent states. For the quantum expectation values calculated with respect to these semiclassical states we obtain for the operators of the coordinates, momenta, and isospin of the particle Hamiltonian equations of motion that are equivalent (in the relativistic case after transition to the proper time) to Wong's well-known equations for a non-Abelian charge with isospin 1/2.