Li Xiaoqin, Wu Yanwen, Steel Duncan, Gammon D, Stievater T H, Katzer D S, Park D, Piermarocchi C, Sham L J
Frontiers in Optical Coherent and Ultrafast Science (FOCUS), Harrison M. Randall Laboratory of Physics, The University of Michigan, Ann Arbor, Michigan 48109-1120, USA.
Science. 2003 Aug 8;301(5634):809-11. doi: 10.1126/science.1083800.
We report coherent optical control of a biexciton (two electron-hole pairs), confined in a single quantum dot, that shows coherent oscillations similar to the excited-state Rabi flopping in an isolated atom. The pulse control of the biexciton dynamics, combined with previously demonstrated control of the single-exciton Rabi rotation, serves as the physical basis for a two-bit conditional quantum logic gate. The truth table of the gate shows the features of an all-optical quantum gate with interacting yet distinguishable excitons as qubits. Evaluation of the fidelity yields a value of 0.7 for the gate operation. Such experimental capability is essential to a scheme for scalable quantum computation by means of the optical control of spin qubits in dots.
我们报告了对单个量子点中双激子（两个电子 - 空穴对）的相干光学控制，该双激子表现出类似于孤立原子中激发态拉比振荡的相干振荡。双激子动力学的脉冲控制，与先前展示的单激子拉比旋转控制相结合，构成了一个两位条件量子逻辑门的物理基础。该门的真值表显示了一个全光量子门的特征，其中相互作用但可区分的激子作为量子比特。对门操作保真度的评估得出值为0.7。这种实验能力对于通过量子点中自旋量子比特的光学控制实现可扩展量子计算的方案至关重要。
