论文标题
高度各向异性半导体中双量子点中的孔旋转Qubit的交换相互作用
Exchange interaction of hole-spin qubits in double quantum dots in highly anisotropic semiconductors
论文作者
论文摘要
我们研究了在磁场和电场的存在下，在硅纳米线中的双量子点设置中，两个孔旋转量矩之间的交换相互作用。基于对称性论点，我们表明，即使在高度各向异性的半导体中，也存在有效的自旋，前提是系统与所施加磁场的方向具有双重对称性。这一发现促进了量子基础状态的定义，并简化了耦合量子点中两分门的交换相互作用的形式。如果沿通用方向施加磁场，则立方各向异性术语是一种有效的自旋轨道相互作用，即使是用于反转对称的设置，也引入了新型交换耦合。考虑到硅纳米线双点的示例，我们介绍了这些各向异性交换交互项的相对强度，并计算$ \ sqrt {\ text {swap}} $ gate的保真度。此外，我们表明，各向异性诱导的自旋轨道效应可以与直接RASHBA自旋轨道相互作用相媲美，以实验可行的电场强度。
We study the exchange interaction between two hole-spin qubits in a double quantum dot setup in a silicon nanowire in the presence of magnetic and electric fields. Based on symmetry arguments we show that there exists an effective spin that is conserved even in highly anisotropic semiconductors, provided that the system has a twofold symmetry with respect to the direction of the applied magnetic field. This finding facilitates the definition of qubit basis states and simplifies the form of exchange interaction for two-qubit gates in coupled quantum dots. If the magnetic field is applied along a generic direction, cubic anisotropy terms act as an effective spin-orbit interaction introducing novel exchange couplings even for an inversion symmetric setup. Considering the example of a silicon nanowire double dot, we present the relative strength of these anisotropic exchange interaction terms and calculate the fidelity of the $\sqrt{\text{SWAP}}$ gate. Furthermore, we show that the anisotropy-induced spin-orbit effects can be comparable to that of the direct Rashba spin-orbit interaction for experimentally feasible electric field strengths.
