Merging "nano", rare-earths, and nonlinear crystals: key technology for large-scale quantum networks

融合“纳米”、稀土和非线性晶体：大规模量子网络的关键技术

• 批准号: RGPIN-2015-05477
• 负责人: Tittel, Wolfgang
• 金额: $ 5.17万
• 依托单位: University of Calgary
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=613576
• 关键词: Merging; nano; rare; earths; nonlinear

The economic, political, and social well-being of Canada depends crucially on secure electronic communications, e.g. for e-banking, e-health, e-commerce, and e-government. Yet, current public key crypto systems rely on unproven assumptions about computational complexity, are susceptible to algorithmic advances and better classical computer technology, and will become obsolete with the advent of the quantum computer. Hence, the secrecy of messages encoded and sent in the past or present, even if still ensured today, is vulnerable to future improvements in code breaking, which may lead to decoding of recorded messages with insufficient protection before they lose importance. Quantum key distribution (QKD), which employs individual photons prepared in specific quantum states as carriers of information, promises the ultimate solution to these problems: security that cannot be compromised by new technology. Yet, as photons get lost during transmission, and amplifiers cannot be used due to a fundamental restriction of quantum mechanics known as the no-cloning theorem, QKD currently faces a distance limit of around 200 km. Interestingly, this limit can be removed through not-yet-existing quantum repeaters. Initiating the combination of three immensely successful areas – photon pair generation using non-linear crystals, optical quantum memory in rare-earth-ion-doped crystals, and nano-technology –, the goal of this Discovery Grant is to create key technology for, and remove the impediment to building, such a quantum repeater. More precisely, we will combine a novel way of generating spectrally multiplexed entangled photon pairs, a not-yet-demonstrated non-destructive measurement of the number of photons in a weak signal, and fundamentally improved quantum memory for photons using nano-structured rare-earth-ion-doped crystals. This will allow us to create, in a heralded and spectrally multiplexed fashion, individual photons that are one by one entangled with single collective excitations in the crystal. This ambitious and so-far unaccomplished goal squarely aligns with our long-term aim of provable secure communication across the North American continent. In addition to creating highly qualified personnel at various career levels and advancing the fields of quantum optics, quantum communication and nano-technology, the research project will thus ensure that Canada, after a lot of investment into QKD during the past decade, remains competitive in this important area.

加拿大的经济、政治和社会福祉很大程度上取决于安全的电子通信，例如电子银行、电子医疗、电子商务和电子政务，然而，当前的公钥加密系统依赖于未经证实的假设。计算复杂性，容易受到算法进步和更好的经典计算机技术的影响，并且随着量子计算机的出现而变得过时。因此，过去或现在编码和发送的消息的保密性，即使在今天仍然得到保证，也很容易受到影响。未来的改进密码破解可能会导致在失去重要性之前对记录的信息进行解码，而量子密钥分配（QKD）采用特定量子态中准备的单个光子作为信息载体，有望解决这些问题：安全性。然而，由于光子在传输过程中会丢失，并且由于量子力学的基本限制（称为不可克隆定理）而无法使用放大器，QKD 目前面临着 200 左右的距离限制。公里。暗示，这个限制可以通过尚不存在的量子中继器来消除。 启动了三个极其成功的领域的结合——使用非线性晶体的光子对生成、稀土离子掺杂晶体中的光学量子存储器以及纳米技术——这一发现补助金的目标是创造关键技术，更准确地说，我们将结合一种生成光谱复用纠缠光子对的新方法，这是一种尚未证实的非破坏性数字测量方法。微弱信号中的光子，以及使用纳米结构的稀土离子掺杂晶体从根本上改进了光子的量子存储，这将使我们能够以一种预示的、光谱复用的方式创建一一纠缠的单个光子。这一雄心勃勃且迄今为止尚未实现的目标与我们在整个北美大陆建立可证明的安全通信的长期目标完全一致，此外还培养了各个职业级别的合格人才。该研究项目将推动量子光学、量子通信和纳米技术领域的发展，从而确保加拿大在过去十年对 QKD 进行大量投资后，在这一重要领域保持竞争力。