Departamento de Física Aplicada, Antiguo Hospital de la Marina, Campo Muralla del Mar, UPCT, Cartagena, 30202, Murcia, Spain.
Nanoscale Res Lett. 2013 May 16;8(1):242. doi: 10.1186/1556-276X-8-242.
The aim of this work was to design and control, using genetic algorithm (GA) for parameter optimization, one-charge-qubit quantum logic gates σx, σy, and σz, using two bound states as a qubit space, of circular graphene quantum dots in a homogeneous magnetic field. The method employed for the proposed gate implementation is through the quantum dynamic control of the qubit subspace with an oscillating electric field and an onsite (inside the quantum dot) gate voltage pulse with amplitude and time width modulation which introduce relative phases and transitions between states. Our results show that we can obtain values of fitness or gate fidelity close to 1, avoiding the leakage probability to higher states. The system evolution, for the gate operation, is presented with the dynamics of the probability density, as well as a visualization of the current of the pseudospin, characteristic of a graphene structure. Therefore, we conclude that is possible to use the states of the graphene quantum dot (selecting the dot size and magnetic field) to design and control the qubit subspace, with these two time-dependent interactions, to obtain the optimal parameters for a good gate fidelity using GA.
这项工作的目的是设计并控制使用遗传算法（GA）进行参数优化的单电荷量子比特量子逻辑门 σx、σy 和 σz，使用两个束缚态作为量子比特空间，在均匀磁场中的圆形石墨烯量子点。所提出的门实现方法是通过量子动力学控制具有振荡电场的量子比特子空间和具有幅度和时间宽度调制的局域（在量子点内）门电压脉冲，从而引入相对相位和状态之间的跃迁。我们的结果表明，我们可以获得接近 1 的适合度或门保真度值，避免泄漏到更高状态的概率。对于门操作，系统演化通过概率密度的动力学以及赝自旋电流的可视化来呈现，这是石墨烯结构的特征。因此，我们得出结论，可以使用石墨烯量子点的状态（选择点大小和磁场）来设计和控制量子比特子空间，使用这两个时变相互作用，使用 GA 获得良好门保真度的最佳参数。
