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

我们正在研究自旋轨道相互作用影响下半导体量子点、多点系统、导线和其他器件中的量子相干自旋操纵和输运。在我们的研究中，几何相起着重要的作用。在第三个资助期，我们建议研究三个子项目：(1)量子点的相干自旋操纵。在这里，我们将研究半导体量子点中自旋与进一步量子自由度耦合的量子相干动力学，探索与量子光学中已知概念的类比。(2)量子点相干自旋相关电子输运。我们将研究自旋轨道相互作用对近藤效应的影响。我们还将考虑结合Josephson和自旋元件的系统，并探索通过Josephson电路操纵自旋的可能性。(3)具有强自旋-轨道耦合的一维导线。基于我们在时间反转对称性保护下的自旋量子比特退相干的经验，我们将研究马约拉纳量子比特的随机几何相位。

We are studying quantum coherent spin manipulations and transport in semiconductor quantum dots, multi-dot systems, wires and other devices under the influence of spin-orbit interaction. In our investigations geometric phases play an important role. For the third funding period we propose to investigate three subprojects: (1) Coherent spin manipulations in quantum dots. Here we will study the quantum coherent dynamics of spins in semiconductor quantum dots coupled to further quan-tum degrees of freedom, exploring analogies to concepts known from quantum optics. (2) Coherent spin-dependent electron transport through quantum dots. We will investigate the influence of the spin-orbit interaction on the Kondo effect. We will also consider systems combining Josephson and spin elements and explore possibilities to manipulate the spin via Josephson circuits. (3) One-dimensional wires with strong spin-orbit coupling. Based on our experience with decoherence of spin qubits protected by time-reversal symmetry we will study the random geometric phases of Majorana qubits.