磁场方向调制的InAs量子点分子量子比特

在有效质量近似条件下研究了由两个垂直耦合自组织InAs量子点组成的双电子量子点分子的电子结构，在此基础上利用系统的总自旋提出了一种磁场方向调制的量子比特方案.电子的相关效应可以导致系统的总自旋在0和1之间转换，值得注意的是，通过调节外部磁场的方向来实现这种转换，而不是像以往那样通过改变外部磁场的大小.结果支持利用系统的总自旋作为磁场方向调制的量子比特的可能性，而且因为高质量的垂直耦合量子点分子的制作工艺已经成熟，所以这是一个非常现实的量子比特设计方案. 关键词： 量子点分子 磁场方向调制 量子比特

Two-electron InAs quantum-dot-molecular qubit modulated by the orientation of magnetic fields

The electronic structure of a two-electron quantum-dot molecular has studied using the effective mass approximation. The quantum-dot molecular consists of two vertically coupled self-assembled quantum disks in a magnetic field with varying orientation. Based on the calculation, a qubit modulated by the orientation of magnetic field is proposed with the total spin of the system. Electron correlations may lead to the switching of the total spin between S=0 and S=1 states. The switching is realized not by the changing strength but by the changing orientation of an external magnetic field. Our results provide a possibility to use the total spin of the system as a qubit modulated by varying the orientation of the magnetic field. Since high-quality vertically stacked quantum disks can be fabricated successfully, it is realistic to obtain qubits of this type.