Non-Hermitian operators, localization problem, and the conservation of fermion number
The well-known localization problem for relativistic particles in quantum theory is considered. It is suggested that the non-Hermitian position operator describes two real physical quantities, a center of mass position and an internal helicity (which the author identifies with the fermion number). Hence such a particle is in some vague sense extended.
scientific article; zbMATH DE number 4003007