Department of Physics, Princeton University, Princeton, NJ 08544, USA.
Science. 2010 Feb 5;327(5966):669-72. doi: 10.1126/science.1183628.
Rapid coherent control of electron spin states is required for implementation of a spin-based quantum processor. We demonstrated coherent control of electronic spin states in a double quantum dot by sweeping an initially prepared spin-singlet state through a singlet-triplet anticrossing in the energy-level spectrum. The anticrossing serves as a beam splitter for the incoming spin-singlet state. When performed within the spin-dephasing time, consecutive crossings through the beam splitter result in coherent quantum oscillations between the singlet state and a triplet state. The all-electrical method for quantum control relies on electron-nuclear spin coupling and drives single-electron spin rotations on nanosecond time scales.
实现基于自旋的量子处理器需要对电子自旋态进行快速相干控制。我们通过在能级谱中扫过一个 singlet-triplet 反交叉，演示了双量子点中电子自旋态的相干控制。该反交叉可作为输入自旋单态的分束器。在自旋退相干时间内执行时，连续穿过分束器导致在单态和三态之间产生相干量子振荡。这种全电量子控制方法依赖于电子-核自旋耦合，并在纳秒时间尺度上驱动单电子自旋旋转。
