Rubio, JesúsLuis Aina, Alfredo2023-06-192023-06-192014-05-221050-294710.1103/PhysRevA.89.052128https://hdl.handle.net/20.500.14352/34648©2014 American Physical Society. A.L. acknowledges support from Projects No. FIS2012-35583 of the Spanish Ministerio de Economía y Competitividad and No. QUITEMAD S2009-ESP-1594 of the Consejería de Educación de la Comunidad de Madrid.We address the propagation of the spin along classical trajectories for a spin-1/2 particle obeying the Dirac equation with scalar potentials. Focusing on classical trajectories as the exact propagation of wave-function discontinuities, we find an explicit spin-transport law for the case of the Dirac oscillator. In the general case we examine the spin propagation along classical trajectories emerging as an approximation of the quantum dynamics via the mechanical analog of the optical eikonal asymptotic approach. Throughout we establish as many parallels as possible with the equivalent situation for the electromagnetic field.engjournal articlehttp://dx.doi.org/10.1103/PhysRevA.89.052128http://journals.aps.org/open access535Dirac-equationOptical fibersPolarizationRotationÓptica (Física)2209.19 Óptica Física