Effects of spin-orbit interaction and geometric phases on quantum coherent spin transport and spin manipulations in semiconductor quantum dots and devices

We propose to study quantum coherent spin transport and spin dynamics in semiconduct-ing quantum dots, multi-dot systems, and devices under the influence of spin-orbit interac-tion and geometric phases. Specifically we plan to investigate three subprojects: (i) We will explore how these effects can be used to control the quantum gates needed for spin-based quantum information processing purely by means of ac electric fields applied to the quantum dots. (ii) We will investigate the influence of spin-orbit interaction on geometric relaxation and decoherence processes at low magnetic fields pointing in arbitrary direction, as well as multipolar contributions at high fields, and we want to explore strategies to enhance the coherence time, e.g., by exploiting motional narrowing. (iii) We will study spin-dependent higher order correlated tunneling processes, an example being provided by the Kondo effect in transport through systems where a quantum dot is in contact with ferromagnetic electrodes. We plan to study the influence of spin textures arising due to spin-orbit interaction on the transport characteristics as well as the interplay of spin and orbital degrees of freedom in multi-dot systems. Much of our theoretical work is motivated by recent and ongoing experiments.