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International Collaborative Research Centre TRR 160:
Coherent manipulation of interacting spin excitations in tailored semiconductors.

  • A4 Coherent control of the electronic and nuclear spins in quantum dot ensembles

    The project is focused on the theoretical description of coherent control and dynamic spin polarization in ensembles of quantum dots based on ultrafast pumping by optical laser pulses. We describe the radiative decay of the intermediate trion states simultaneously considering the hyperfine coupling to the nuclear spin bath, the dipole-dipole interaction among the nuclear spins, and the nuclear quadrupolar interaction induced by strain fields. Quantum mechanical, semi-classical and classical techniques combined with Lindblad master equations will be employed to assess the effect of pulses and trains of pulses and to suggest protocols for generalized dynamic decoupling to suppress decoherence.

  • A7 Theory of spin-noise in semiconductor quantum dots

    Spin-noise spectroscopy is a promising technique for revealing the microscopic nature of spin decoherence processes in quantum dots. Although the hyperfine interaction of the electron spin and the nuclear spins has been identified as one of the major sources of spin decoherence, there persists a striking mismatch between the theoretical prediction of the spin-noise spectrum obtained within the isotropic central spin model (CSM) and the experimentally measured data. Thus, this project aims at improving our understanding by including the effect of quadrupolar nuclear spin interactions, electron-lattice relaxation processes and charge fluctuations in an extended CSM as well as the effects of anisotropy of the hyperfine interaction.