Engineered photonic qubits for integrated optical quantum computing networks

量子信息处理采用了量子力学的定律，例如适用于单个原子或光子，以一种基本的方式推进了当前计算机和通信系统（如互联网）的基础技术。如果实现，它将允许更快的计算，并且例如将威胁到当前用于秘密通信的加密方案的安全性。它还提供了许多潜在的新型通信方案，包括无条件安全的新型加密方案，即使对量子信息处理也是如此。各种各样的候选技术，如离子阱、光晶格、量子点、超导器件，特别是光子，目前正在探索作为量子信息处理和量子通信实验实现的候选技术。在这种情况下，基于光子的实现发挥了特别重要的作用，因为它们代表了量子信息的理想载体。任何量子通信网络或分布式量子信息处理设备都需要能够在单光子水平上相干地操纵光子自由度。对于长距离通信，不可避免的噪声和吸收过程需要使用量子中继器来刷新量子信息。用于这样一个基于光子的系统的中继器需要能够进行小规模的基于光子的量子信息处理。拟议的项目旨在实施所需的技术，采用高度集成的光学设备，而不是更传统的大块光学方法，将单个光学元件排列在光学台上。这种方法避免了大量光学器件所面临的许多问题，并且还允许使用更通用的方法对信息进行编码和操作。我们的目标是探索这种新技术在量子信息处理中的实验和理论应用，以开发量子信息处理的新方法，并证明在这种安排下基本量子信息处理的可行性。

Quantum Information Processing employs the laws of quantum mechanics which apply to individual atoms or photons for example to advance the technology underlying current computers and communication systems such as the internet in an essential way. If realized it would allow for much faster computation and would for example threathen the security of current cryptographic schemes for secret communication. It also offers the potential many novel communication schemes including novel cryptographic schemes that are unconditionally secure, even against quantum information processing. A variety of candidate technologies, such as ion traps, optical lattices, quantum dots, superconducting devices and in particular photons, are currently being explored as candidates for the experimental implementation of quantum information processing and quantum communication. In this context photon based implementations play a particularly important role as they represent ideal carriers of quantum information. Any quantum communication network or distributed quantum information processing device would require the ability to manipulate photonic degrees of freedom coherently at the single photon level. For longer distance communication the unavoidable noise and absorption processes would require the use of quantum repeaters to refresh the quantum information. Repeaters for such a photon-based system would require the ability for small scale photon based quantum information processing.The proposed project aims to implement the required technology employing highly integrated optics devices rather than the more traditional bulk optics approach where one arranges individual optical elements on an optical table. This approach avoids many of the problems that bulk optics suffers and also permits more general ways to code and manipulate information. We aim to explore the use of this novel technology for quantum information processing both experimentally and theoretically to develop novel methods for quantum information processing and to demonstrate the feasibility of basic quantum information processing in such arrangements.