Fabrication and control of nuclear-and electron spin quantum bits

我们对29Si核自旋的量子操纵进行了基础研究，这些自旋是在同位素控制的硅单晶中被人为地以明确的方式放置的。这里的自旋操纵是指通过适当的脉冲射频序列照射来初始化（偏振增强）和延长相相干时间。作为第一步，我们已经成功地理解了硅表面的物理特性，以一种非常明确的方式适当地放置特定的硅同位素，并成功地实现了适合硅核自旋量子计算的原子阵列。我们还提出了利用光或电子自旋共振初始化29Si核自旋的新方法，并通过将核自旋极化提高三个数量级的实验证实了它们的有效性。同时，我们成功地将室温下的相位相干时间延长到25秒。对于读出，我们提出了基于光或电子自旋共振的新方法，并实验证明了硅中核自旋态的成功读出。

We have performed fundamental research on quantum manipulation of 29Si nuclear spins that are artificially placed in a well-defined manner in isotopically controlled silicon single crystals. Here spin manipulation refers to as initialization (polarization enhancement) and extension of phase coherence time by appropriate irradiation of pulsed radio frequency sequences.As a first step, we have successfully understood physics of silicon surfaces for appropriate placing of specific silicon isotopes in a very well-defined manner and succeeded in realization of atomic arrays that were suitable for silicon nuclear spin quantum computation. We have also proposed new methods to initialize 29Si nuclear spins using either light or electron spin resonance, and confirmed their effectiveness experimentally by increasing the nuclear spin polarization by the three orders of magnitude. In parallel, we have succeeded in extension of the phase coherence time up to 25 seconds at room temperature. For the readout, we have proposed new methods based on light or electron spin resonance and experimentally demonstrated successful readout of the nuclear spin states in silicon.