Starts 5 Apr 2016 11:30
Ends 5 Apr 2016 12:30
Central European Time
Abstract: We have analyzed effects of the hyperfine interaction on electric dipole spin resonance (EDSR) when the amplitude of the quantum-dot motion becomes comparable or larger than the quantum dot's size. Away from the well-known small-drive regime, the important role played by transverse nuclear fluctuations leads to a gaussian decay of spin coherence with characteristic dependence on drive strength and detuning. A characterization of spin-flip gate fidelity, in the presence of such additional drive-dependent dephasing, shows that vanishingly small errors can still be achieved at sufficiently large amplitudes. Based on our theory, we analyze recent EDSR experiments relying on spin-orbit interactions or the slanting field of a micromagnet. We find that such experiments are already in a regime with significant effects of transverse nuclear fluctuations and the form of decay of the Rabi oscillations can be reproduced well by our theory. We will also briefly discuss other aspects of our research on single and double quantum dots, regarding the controlled generation of Dicke states in the nuclear spin bath and fast electron spin manipulation.