Article

This is a sequel to two earlier papers in which the behaviour of the nonlinear Dirac soliton in an external potential in 1+1 dimensions is examined. Regarding the Lorentz transformation properties there are three types of potentials: vector (V), scalar (S), and pseudoscalar (PS). In this paper we consider the PS potential. Unlike the V and S potentials that we considered earlier, the PS potential has no obvious counterpart in classical mechanics. Still the soliton behaves like a point particle in relativistic classical mechanics with a certain Hamiltonian. Close scrutiny, however, reveals that the soliton undergoes Zitterbewegung. PACS Nos.: 02.30, 03.40Kf, 03.65-w