Institut Néel, CNRS et Université Joseph Fourier, BP 166, F-38042 Grenoble Cedex 9, France.
Nature. 2012 Aug 16;488(7411):357-60. doi: 10.1038/nature11341.
Quantum control of individual spins in condensed-matter devices is an emerging field with a wide range of applications, from nanospintronics to quantum computing. The electron, possessing spin and orbital degrees of freedom, is conventionally used as the carrier of quantum information in proposed devices. However, electrons couple strongly to the environment, and so have very short relaxation and coherence times. It is therefore extremely difficult to achieve quantum coherence and stable entanglement of electron spins. Alternative concepts propose nuclear spins as the building blocks for quantum computing, because such spins are extremely well isolated from the environment and less prone to decoherence. However, weak coupling comes at a price: it remains challenging to address and manipulate individual nuclear spins. Here we show that the nuclear spin of an individual metal atom embedded in a single-molecule magnet can be read out electronically. The observed long lifetimes (tens of seconds) and relaxation characteristics of nuclear spin at the single-atom scale open the way to a completely new world of devices in which quantum logic may be implemented.
在凝聚态设备中对单个自旋的量子控制是一个新兴领域，其应用范围广泛，包括纳米自旋电子学和量子计算。电子具有自旋和轨道自由度，通常被用作所提出的设备中量子信息的载体。然而，电子与环境强烈耦合，因此其弛豫和相干时间非常短。因此，很难实现电子自旋的量子相干和稳定纠缠。替代概念提出核自旋作为量子计算的构建块，因为这些自旋与环境极其隔离，不易退相干。然而，弱耦合是有代价的：仍然难以解决和操纵单个核自旋。在这里，我们展示了嵌入在单个分子磁体中的单个金属原子的核自旋可以通过电子方式读出。在单原子尺度上观察到的核自旋的长寿命（数十秒）和弛豫特性为一种全新的器件世界开辟了道路，在这种器件世界中可以实现量子逻辑。
