Relativistic electron spin motion in cycloatoms

We present computer movies of the classical and quantum mechanical time evo lution for an atom in a strong static magnetic field and a laser field. The resonantly induced relativistic motion of the atomic electron leads to a r ing-like spatial probability density called a cycloatom. We further demonst rate that spin-orbit coupling for a fast moving electron in a cycloatom bec omes significant, modifying the time-dependence of the spin even if initial ly aligned parallel to the static magnetic field direction. We also present several movies on time-evolution of the spin-distribution as a function of the position for a relativistic quantum state. The nature of such a space resolved spin measurement is analyzed. (C) 2001 Optical Society of America.