Fermionic solitons in gauge theories and their quantum corrections

Fermionic solitons are defined in terms of localized self-consistent solutions of the classical equations of motion for bosons and Dirac fields. The one-loop quantum-mechanical correction to the mass of such a state is given by the diagonal S-matrix element in a self-consistent interaction picture. The various contributions to the energy shift are discussed, and the gauge invariance of our result is verified explicitly. Our operator formulation for fermionic solitons is shown to be equivalent to a Feynman path-integral prescription proposed by Dashen, Hasslacher, and Neveu