A photonic link for silicon donor-based quantum technologies

硅晶体管是大多数现代电子设备的基本组成部分，如果没有量子力学的影响，它不可能进一步缩小。这个经典量子阈值实际上提供了一个巨大的机会：如果我们利用量子力学，而不是试图避免它，我们就可以建造一台量子计算机，它可以完成某些否则永远不切实际的计算任务。许多用于药物模拟、大数据优化、线性代数、机器学习等的基础计算将变得成倍地快，因此有可能在现实的时间尺度上求解。 最有希望的候选量子比特之一(量子比特)是由硅中的施主杂质制成的：正是原子缺陷阻碍了最小的晶体管正常工作。我已经证明，这些量子比特具有最长的固态寿命(&gt；3小时)和最好的固态量子控制特性(&gt；99.9%的准确度)。这些优秀的单个量子比特也具有关键的商业优势：它们在原子上是相同的，可以使用制造现代硅晶体管的相同技术来制造。这一点很重要，因为量子计算机仍将需要芯片上集成的“经典”计算能力才能有效运行。 目前急需的是在这些原子量子比特之间建立连接或耦合的可靠方法，我们需要发明某种相当于硅中的量子晶体管的东西。我提出的实现这一目标的解决方案是全新的。我计划通过光子量子比特来调节硅原子量子比特的相互作用，从而将它们联系起来。这可以通过许多方法来完成：一种方法是在原子和光子量子比特之间交换量子信息。这一策略将利用硅中的光子结构，例如，这种结构可以沿着硅器件内的预定路径引导光。这些结构与为光纤设备开发的结构非常相似，可以可靠地连接多个原子量子比特。设计简单，实验公差大。我的研究计划面临的最大风险是它的紧迫性第一个证明硅中的量子晶体管将获得不可逾越的先发优势的研究小组。 这一研究计划的成功将使硅原子量子比特在走向大规模量子计算机的国际竞赛中处于领先地位。随之而来的计算能力革命将对整个世界产生巨大影响，其方式我们还无法预测。想象一下，仅仅基于对1946年第一台巨大的、耗电的、基于真空管的数字计算机的评估，就可以预测现代信息技术的无处不在。如果能够为硅开发量子信息晶体管，它将为硅再次彻底改变信息时代铺平道路。

Silicon transistors, the essential building block of most modern electronic devices, cannot shrink much further without being rendered inoperable by quantum mechanics. This classical-quantum threshold in fact presents a tremendous opportunity: if we harness quantum mechanics, rather than attempt to avoid it, we could build a quantum computer, which could accomplish certain computational tasks that would otherwise be forever impractical. Numerous fundamental calculations for drug simulations, big-data optimization, linear algebra, machine learning, and more, would become exponentially faster and therefore possible to solve on a realistic timescale. One of the most promising candidate quantum bits (qubits') are made from donor impurities in silicon: the very atomic defects preventing the smallest transistors from working properly. I have shown that these qubits have the longest solid-state lifetimes (>3 hrs) and the best solid-state quantum control properties (>99.9% accuracy) ever demonstrated. These excellent individual qubits also have key commercial advantages: they are atomically identical, and can be fabricated using the same techniques used to build modern silicon transistors. This is important because quantum computers will still need on-chip integrated “classical” computing power to operate effectively. What is urgently lacking is a reliable way to build connections, or couplings', between these atomic quantum bits we need to invent something equivalent to a quantum transistor in silicon. My proposed solution to accomplish this is radically new. I plan to link silicon atomic qubits by mediating their interactions via photon qubits. This can be done in a number of ways: one way is to swap the quantum information between the atomic and photonic qubits. This strategy will make use of photonic structures in silicon which can, for example, direct light along predetermined paths within a silicon device. These structures, which are very similar to the ones developed for fibre-optics devices, could reliably link multiple atomic qubits. The designs are simple and the experimental tolerances are large. The biggest risk to my research plan is its urgency the first research group to demonstrate a quantum transistor in silicon would gain an insurmountable first-mover advantage. The success of this research plan would launch silicon atomic qubits to the frontrunner position in the international race toward a large-scale quantum computer. The resulting revolution in computing power would have an enormous effect on the whole world, in ways we cannot yet predict. Imagine predicting the ubiquity of modern information technology based only on an evaluation of the first, huge, power-hungry, vacuum-tube-based digital computer in 1946. If quantum-information transistors can be developed for silicon, it will pave the way for silicon to revolutionize the information age once again.