Investigating deep defects in 28Si for potential applications in quantum information and communication

我们的现代技术是基于量子力学完美描述纳米级系统行为的能力（如果只是概率上的）。人们越来越认识到，量子力学原理可以更直接地应用于新的“量子技术”，这些技术在通信、安全和计算领域具有全新的、潜在的颠覆性应用的惊人潜力。在量子计算机（QC）中，叠加允许传统计算机位的0和1被无限范围的0和1的叠加所取代，从而产生一个量子比特或量子位。量子比特可以通过纠缠连接起来，这样对一个量子比特的测量就会影响另一个量子比特的测量结果，即使它们是分开的。这违背了我们的直觉，因为它是基于宏观现实的，但可以完全用量子力学来解释。我们现在知道，对于某些类型的重要问题，QC可能比可以想象到的最大的传统计算机更强大、更快。这种范式转换的潜力正在推动世界各地的激烈研究，以找到一种技术，使质量控制足够复杂，以解决这类广泛的问题。广泛的系统正在被研究，从光子到原子再到亚原子粒子，如电子和核自旋。许多活动都集中在基于硅（Si）的方法上，因为硅是我们当前计算和信息技术的基础。如果能够开发出合适的量子比特以及制备、耦合和测量它们的方法，现有的硅材料科学和纳米级器件技术可以用来构建一个QC。我们发现富集的28Si具有独特的性质：28Si的光学跃迁的线宽比普通Si（或任何其他半导体）的线宽要锋利得多，这导致了控制和测量杂质的电子和核自旋的新方法，这些杂质是Si中量子比特的主要候选者。这些技术证明了创纪录的相干寿命——一个量子位可以维持的时间——这引起了全球的广泛关注，包括2013年物理学世界十大突破。使用这些相同的技术，我们最近发现了制造与硅光子学兼容的高度可重复的单光子源的全新可能性，这解决了那些试图构建基于光子的量子技术的突出需求。这些令人兴奋的单光子源还提供了一种将芯片上的多个量子比特与单个光粒子连接起来的方法，为大规模硅基QC铺平了道路。这笔赠款将使我们能够在我们的成就和合作的基础上再接再厉，并继续在这一领域制定新的方向。具体来说，我们将培养具有半导体，光学，低温和量子信息理论专业知识的未来领导者，他们将为实现量子技术的承诺做出贡献。

Our modern technology is based on the ability of quantum mechanics to describe perfectly (if only probabilistically) the behavior of nanoscale systems. There is a growing appreciation that the principles of quantum mechanics can be used more directly in new `quantum technologies', which have spectacular potential for completely new and potentially disruptive applications in communications, security, and computing. In a quantum computer (QC), superposition allows the 0 and 1 of a conventional computer bit to be replaced by an infinite range of superpositions of 0 and 1, giving a quantum bit, or qubit. Qubits can be linked using entanglement so that a measurement on one affects the outcome of a measurement on the other, even when separated. This defies our intuition, based as it is on macroscopic reality, but can be completely accounted for by quantum mechanics. We now know that for certain classes of important problems, a QC could be enormously more powerful and faster than the largest imaginable conventional computer. This paradigm-shifting potential is fueling intense research around the world to find a technology for making a QC of sufficient complexity to solve this broad class of problems. A wide range of systems is being investigated, from photons to atoms to subatomic particles such as electrons and nuclear spins. Much activity is focused on silicon (Si)-based approaches, since Si is the basis for our present computing and information technologies. The existing Si materials science and nanoscale device technology could be harnessed to build a QC, if suitable qubits and the means of preparing, coupling and measuring them can be developed. Our discovery that enriched 28Si has a unique property: the linewidths of optical transitions are much sharper in 28Si than in normal Si (or in any other semiconductor), led to new methods for controlling and measuring the electron and nuclear spins of impurities, which are prime candidates for qubits in Si. These techniques demonstrated record-setting coherence lifetimes - the time for which a qubit can be maintained - which attracted significant global attention, including a Physics World Top Ten Breakthrough of the Year (2013). Using these same techniques, we recently identified entirely new possibilities for making highly reproducible single photon sources compatible with Si photonics, which addresses an outstanding need for those trying to build photon-based quantum technologies. These exciting single photon sources also offer a way to link multiple qubits on-chip with individual particles of light, paving the way towards a large-scale silicon-based QC. This grant will allow us to build on our achievements and collaborations, and to continue to set new directions in this field.  Specifically, we will train future leaders, equipped with expertise in semiconductors, optics, cryogenics and quantum information theory, who will contribute to making the promise of quantum technologies a reality.