AF: Large: Collaborative Research: Reliable Quantum Communication and Computation in the Presence of Noise

量子信息科学对信息和通信的本质产生了深刻的理论见解，同时也带来了更强大的计算机和通信网络的希望。 但这些实际目标的实现受到量子信息固有的脆弱性的阻碍。通过简单冗余获得可靠性的传统方法不起作用;相反，容错必须，并且可以，在原则上，通过微妙的技术，设法测量和纠正错误，而不学习任何关于编码的data.不幸的是，目前的容错量子计算的方法需要显着的开销，目前的量子信道容量的理解仍然非常有限。 例如，没有已知的量子代码可以在不离开代码空间的情况下执行任意容错量子计算。 直到最近才发现，经典信息可以以超过长期限制的Holevo界限的速率发送。该项目将试图开发在存在噪声的情况下进行可靠量子通信和计算的新方法。 首先，这项研究将推动量子纠错技术的能力和边界，既通过扩展和描述可纠正错误的类型，也通过确定这种纠错是可能的或不可能的情况。 第二个目标是发展量子码、纠缠、多体物理学、复杂性理论、密码学和高维几何学之间的深层但迄今为止尚未探索的联系。 其目的是促进我们对量子码以及数学，物理和计算机科学相关领域的理解。 最后，研究小组将试图阐明量子通信与其最接近的经典模拟--私人通信之间的细微差异。这项研究致力于为大规模量子计算机的现实实施做出决定性贡献，这将大大提高人类处理和交流信息的能力。 研究项目本身是跨学科的，汇集了来自工业界和学术界的物理学家，计算机科学家和数学家，并培训学生和博士后。

Quantum information science has yielded deep theoretical insights into the nature of information and communication, while raising the hope of dramatically more capable computers and communication networks. But the achievement of these practical goals is hindered by the inherent fragility of quantum information. Traditional approaches for obtaining reliability through simple redundancy do not work; instead, fault tolerance must, and can, in principle, be obtained through subtler techniques that contrive to measure and correct errors without learning anything about the encoded data.Unfortunately present methods for fault-tolerant quantum computation require significant overhead, and present understanding of quantum channel capacities remain very limited. For example, no quantum code is known on which arbitrary fault-tolerant quantum computation can be performed without leaving the code space. And only very recently was it discovered that classical information can be sent at rates exceeding the long-conjectured Holevo bound.This project will attempt to develop new methods for reliable quantum communication and computation in the presence of noise. First, the research will push the capabilities and boundaries of quantum error-correction techniques, both by extending and delineating the types of correctable errors, and by determining the scenarios under which such error correction is or is not possible. The second goal is to develop the deep but heretofore largely unexplored connections between quantum codes, entanglement, and many-body physics, complexity theory, cryptography and high-dimensional geometry. The objective is to advance our understanding both of quantum codes as well as the related areas of mathematics, physics and computer science. Finally the team will seek to elucidate the subtle differences between quantum communication and its closest classical analog---private communication.This research endeavors to contribute definitively to realistic embodiments of large-scale quantum computers, which would dramatically improve mankind's ability to process and communicate information. And the research program itself is deeply interdisciplinary, bringing together physicists, computer scientists and mathematicians from industry and academia, and training students and postdocs.