Semiclassical quantization of Hopf solitons

The gauge-equivalent formulation of the Faddeev–Skyrme model is used for the study of the quantum theory. The rotational quantum excitations around the soliton solution of Hopf number unity are investigated by the method of collective coordinates. The quantum Hamiltonian of the system is found to coincide with the Hamiltonian of a symmetrical top rotating in SU(2). Thus, the irreducible representations of physical observables can be constructed.