Quantum optics using Rydberg polaritons

最小的光被称为光子。尽管光子很多，但逐个控制它们仍然是一项挑战。如果我们能获得更多的控制权，我们就能在许多领域取得巨大的进步，包括成像、传感、计算和通信。在这个项目中，我们的目标是使用一种被称为里德伯原子的特殊类型的原子来获得对单个光子的更多控制。在里德伯原子中，一个电子被激发到一个平均离原子核很远的状态。在里德伯状态下，原子的性质被大大夸大了。特别是，它对附近的里德伯原子非常敏感。在过去的十年里，我们在达勒姆展示了如何将里德伯原子之间的这种灵敏度映射到光子之间的强相互作用中。这个想法被称为里德伯量子光学，它导致了迄今为止所证明的光子之间最强的相互作用。里德伯量子光学之旅的下一步是使这个系统更有用。我们提出的一个重要的实用步骤是将里德伯量子光学的显著特征与集成光子学的能力结合起来。我们将使用基于光纤耦合芯片的架构来按需投射单光子并控制光子之间的相互作用。此外，我们将展示如何将这些器件与基于冷原子的量子存储器相连接。另一个重要的挑战是使Rydberg光子学技术相关的基础物理和潜在的设备更快地工作。目前的速度限制在每秒兆位的范围内。在这个项目中，我们将探索当我们尝试将其扩展到每秒千比特的范围时会发生什么。除了提高数据速率，速度更快还有另一个好处，那就是我们对原子运动不那么敏感，而原子运动目前是降低效率的过程之一。本提案中展示的步骤将为实现量子互联网的梦想提供重大进展。

The smallest amount of light is known as a photon. Although photons are plentiful, controlling them one-by-one remains challenging. If we could gain more control we could make tremendous advances in many areas including imaging, sensing, computing and communications.In this project, we aim to gain more control over individual photons using a special type of atom known as a Rydberg atom. In a Rydberg atom, one electron is excited to a state where it is on average very far from the nucleus. In this Rydberg state, the atom has greatly exaggerated properties. In particular, it becomes extremely sensitive to nearby Rydberg atoms. Over the last decade in Durham, we have shown how to map this sensitivity between Rydberg atoms into a strong interaction between photons. This idea, known as Rydberg quantum optics, has resulted in the strongest interaction between photons ever demonstrated.The next steps on this Rydberg quantum optics journey is to make this system more useful. A major step change in utility that we are proposing is to combine the remarkable features of Rydberg quantum optics with the power of integrated photonics. We will use a fibre coupled chip-based architecture to project single photons on demand and control the interactions between photons. In addition, we will show how these devices can be interfaced with cold atom based quantum memories. Another important challenge to make Rydberg photonics technologically relevant is to make underlying physics and potential devices work faster. Currently the speed limit is in the range of Mbits per second. In this project, we will explore what happens when we try to extend this into the Gbits per second range. As well as increase data rates, going faster also has another advantage in that we become less sensitive to atomic motion which is currently one of the processes that degrade efficiency.The steps demonstrated in this proposal will facilities significant progress towards the dream of a quantum internet.