2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/23399We study a non-adiabatic excitation of an electron system in a 1D quantum ring radiated by a short THz pulse. The response of two models, a continuous and discrete, is explored. By introducing a spatial asymmetry in the external perturbation a net current can be generated in the ring at a zero magnetic field. Effect of impurities and ratchets are investigated in combination with symmetric and asymmetric external excitation.LaTeX 4 pages with 6 embedded postscript figuresMesoscale and Nanoscale Physicstext