Coherent rotations of single spin-based qubits may be accomplishedelectrically at fixed Zeeman energy with a qubit defined solely within a singleelectrostatically-defined quantum dot; the $g$-factor and the external magneticfield are kept constant. All that is required to be varied are the voltages onmetallic gates which effectively change the shape of the elliptic quantum dot.The pseudospin-1/2 qubit is constructed from the two-dimensional $S=1/2$,$S_z=-1/2$ subspace of three interacting electrons in a two-dimensionalpotential well. Rotations are created by altering the direction of thepseudomagnetic field through changes in the shape of the confinement potential.By deriving an exact analytic solution to the long-range Coulomb interactionmatrix elements, we calculate explicitly the range of magnitudes and directionsthe pseudomagnetic field can take. Numerical estimates are given for {GaAs}.
展开▼
机译：基于自旋的量子位的相干旋转可以在固定的塞曼能量下以电方式完成，而量子位仅在单个静电定义的量子点内定义； $ g $因子和外部磁场保持恒定。只需改变金属栅极上的电压即可有效地改变椭圆量子点的形状.pseudospin-1 / 2 qubit由二维$ S = 1/2 $，$ S_z = -1构造二维势阱中三个相互作用电子的/ 2 $子空间。通过改变约束电位的形状来改变伪磁场的方向来产生旋转。通过对长距离库仑相互作用矩阵元素求出精确的解析解，我们可以明确地计算出伪磁场可以采取的幅度和方向范围。给出了{GaAs}的数值估计。
展开▼
