Revivals, collapses and magnetic-pulse generation in quantum rings
  Using a microscopic theory based on the density matrix formalism we investigate quantum revivals and collapses of the charge polarization and charge current dynamics in mesoscopic rings driven by short asymmetric electromagnetic pulses. The collapsed state is utilized for sub-picosecond switching of the current and associated magnetization, enabling thus the generation of pulsed magnetic fields with a tunable time structure and shape asymmetry which provides a new tool to study ultrafast spin-dynamics and ratchet-based effects. 
A.S. Moskalenko, A. Matos-Abiague, J. Berakdar