Fermion fractionization in physics

When a fermion is introduced to a soliton the fermion can split up and its quantum numbers shared by the resulting states. Thus fractional charge can emerge in a theory where all basic constituents carry integral charges. This quantum mechanical-topological phenomenon is discussed. A one-dimensional fermion-soliton system is possible in condensed situations as a description of an electron (fermion) in the presence of a domain wall (soliton). An example is discussed - this is in the case of polyacetylene, where the peculiar experimental results can be explained by the peculiar behaviour of fermions/solitons. (U.K.)