Spin-orbit pendulum (relativistic extension)

We discuss an extension of the theory of spin-orbit pendulum phenomenon to relativistic approach. It is done within the so called Dirac Oscillator. Ou r first results, focusing on circular wave packet motion have been publishe d recently. The scope of this paper is motion of a linear wave packet. In r elativistic approach we found Zitterbewegung in spin-orbit motion (in Dirac representation) due to coupling to negative energy states. This effect is washed out in the Foldy-Wouthuysen representation. Another important change with respect to non-relativistic case is the loss of periodicity. The phen omenon reminds the time evolution of population inversion in Jaynes-Cumming s model.