From Quantum Communication to Quantum Internet

有人说，人类对书面材料保密的愿望几乎和文字本身一样古老。随着互联网的兴起，加密的重要性与日俱增。不幸的是，传统的加密方案通常基于计算假设，因此容易受到算法和硬件(包括量子计算)的意外进步的影响。幸运的是，量子密码学提供了无条件的安全-安全通信的圣杯-基于物理定律。中国和英国等国目前正在建设量子加密网络。尽管如此，量子密码学的理论和实践之间仍有很大差距。量子黑客威胁着实用量子密钥分发系统的安全。 在这个方案中，我们将首先设计出实用的手段来挫败量子黑客，从而重新建立量子密钥分发(QKD)的安全性。其次，我们将构建基于硅片的量子密钥分发，这将大大降低量子密钥分发的成本。第三，我们将设计和建设灵活可重构的量子网络。这样的网络非常适合大城市距离内的应用。第四，我们将发展我们的所有光子学量子中继器的理论建议，目标是使其实用化。我们的方案的优点是消除了对量子存储器的苛刻要求。量子中继器是量子互联网的重要使能技术，它允许在全球范围内进行安全的量子通信。量子互联网有许多有用的应用，包括量子云计算。第五，我们将作为欧洲太空探索项目的团队成员，探索太空中的纠缠科学。 这项提案中上述五个研究领域的成功将使我们离量子计算机用于量子化学模拟的未来更近一步，从而大大加快化学和生物分子和结构的设计和分析，并使通过量子密码进行无条件安全通信成为常规。

It has been said that the human desire to keep written material a secret is almost as old as writing itself. With the rise of the Internet, the importance of encryption is growing. Unfortunately, conventional encryption schemes are often based on computational assumptions and are therefore vulnerable to unanticipated advances in algorithms and hardware including quantum computing. Fortunately, quantum cryptography offers unconditional security---the Holy Grail of secure communication---based on the laws of physics. Quantum cryptographic networks are currently being built in countries such as China and the UK. Nonetheless, there is a big gap between the theory and practice of quantum cryptography. Quantum hacking threatens the security of practical quantum key distribution systems. In this proposal, we will first devise practical means to foil quantum hackers, thus re-establishing the security of quantum key distribution (QKD). Second, we will construct silicon chip-based QKD which could dramatically lower the cost of QKD. Third, we will design and build quantum networks that are agile and reconfigurable. Such a network is ideal for applications in metropolitan distances. Fourth, we will develop our theoretical proposal of all photonics quantum repeaters with the goal of making it practical. Our proposal has the advantage of removing the demanding requirement of quantum memories. Quantum repeaters are an important enabling technology for the quantum internet which allows secure quantum communication on a global scale. Quantum internet has many useful applications including quantum cloud computing. Fifth, we will explore entanglement science in space through our participation as a team member of the European Space-Quest project. Success in each of the above five research areas in this proposal will bring us one step closer to a future where quantum computers are used for simulations in quantum chemistry, resulting in a dramatic speed up in the design and analysis of chemical and biological molecules and structures, and a future where unconditionally secure communication via quantum cryptography is routine.