Regensburg 2016 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 25: Quantum Information Systems (Joint session of HL and TT, organized by HL)

HL 25.4: Vortrag

Dienstag, 8. März 2016, 10:15–10:30, H15

Spin Decoherence in a Pulsed Quantum Dot System — •Natalie Jäschke and Frithjof Anders — Fakultät Physik, TU Dortmund, 44227 Dortmund, Deutschland

In pump-probe experiments electron spin polarization in a semiconductor quantum dot is generated by periodic optical excitations. The decoherence of this polarization is dominated by the hyperfine interaction with a bath of nuclear spins in the short time regime. We aim for a theory that combines the effect of the periodic laser pulses and the nuclear spin bath on the electron spin polarization. Since the laser pulses occur on the shortest time scale of the system, and the electronic decay times are small compared to those of the nuclear spin bath, we treat the laser pumping quantum-mechanically using a Lindblad approach and keep the nuclear spins as frozen during that time. Then a classical simulation of the Overhauserfield bridges the time until the next laser pulse. We analyze the stability of different non-equilibrium nuclear spin bath distribution functions as well as the magnetic field dependent build up of a laser-induced nuclear spin polarization.