Eur. Phys. J. D 46, 15-20 (2008)
https://doi.org/10.1140/epjd/e2007-00273-7

Relativistic effects in the time evolution of an one-dimensional model atom in a laser pulse

Department of Physics, University of Bucharest, MG-11 Bucharest-Magurele, 077125 Magurele, Romania

Corresponding author: ^a boca@barutu.fizica.unibuc.ro

Received: 29 June 2007
Revised: 27 August 2007
Published online: 26 September 2007

Abstract

We define 1D Volkov states as solutions of the one-dimensional Dirac equation in a time dependent electric field, similar to the Volkov solutions in the three dimensional case. They are eigenspinors of the momentum operator and reduce in the absence of the field to free solutions of positive or negative energy. Then we add a time independent attractive Gausssian potential and, by integrating the Dirac equation for a laser pulse of Gaussian shape, we determine the state which coincides initially with the ground state of the system in the absence of the electric field. Our main objective is the study of the population dynamics on the Volkov states during the pulse action. For different values of the laser pulse intensity and two values of the potential depth, we find that the Volkov states which evolve from free solutions of negative energy are practically not populated, in contrast to the population on free negative energy states.