Quantization of Scalar Field Theory with Internal Symmetry

A simple theoretical model of scalar fields in one spatial dimension with internal symmetry is considered. Assuming the existence of localized classical field configurations, the Schr"{o}dinger picture is used to describe their quantum properties. Using the collective coordinates method for the Schr"{o}dinger equation allows the development of a perturbation theory that accurately describes the symmetry properties of the theory. Examples of $U(1)$ and $SU(2)$ symmetries are analyzed and the discreteness of the energy of bound states is shown as a result of the symmetry of the theory.