Laser-controlled local magnetic field using semiconductor quantum rings

We analize theoretically the dynamics of $N$ electrons localized in a semiconductor quantum ring under a train of phase-locked infrared laser pulses. The pulse sequence is designed to control the total angular momentum of the electrons. The quantum ring can be put in metastable states characterized by a persistent current much stronger than the one generated by an Aharonov-Bohm flux. The local magnetic field created by these currents can be used for a selective quantum control of single spins in semiconductor systems.