EXPLOITING RELATIVITY FOR QUANTUM INFORMATION THEORY

我的研究计划是研究如何利用相对论效应来改进量子信息任务，这是一个在今天已经具有巨大技术重要性的关键话题，在未来几十年更是如此。这些研究的有利之处在于，世界从根本上既是量子的，也是相对论的，这些事实对于设计绝对安全的通信设备和量子计算机非常有用，这些通信设备可以快速执行复杂的计算任务，而这些任务压倒了任何经典可以想象的计算机。事实上，仅仅从物质的量子方面认真对待已经产生了令人印象深刻的技术成就和承诺：量子密码学和通信近年来已经成为技术现实，但量子计算机的实际构建仍然需要更好地理解如何在不受环境令人望而却步的大干扰的情况下有效地存储、操作和读取信息。在等式中加入相对论从根本上改变了整个游戏，正如我在一系列研究论文中所展示的那样，其中一篇在一篇普遍可访问的科学文章中重点介绍了我的工作(Cho，Science 2005)。我建议将这一激动人心的理论研究推进到可以从技术上利用量子信息理论中的相对论效应的地步。相对论不仅产生定量修正，而且在实验室中用于实现量子信息任务的许多物理系统的定性行为中起主导作用。典型的例子是任何涉及光的系统，无论是用于量子信息的传输还是操作。不存在光量子的非相对论近似，也就是所谓的光子，因为它们总是以光速运动。虽然相对论量子理论，俗称量子场论，是基础粒子物理学中一个非常好的研究课题，但量子信息论的研究几乎只专注于人们可以在没有相对论的情况下研究的那些方面。因此，无论是意想不到的障碍(如量子纠缠的相对论退化)，还是量子信息理论的不可想象的可能性(如改进的量子密码学和超灵敏的量子测量设备)都没有被注意到。在过去的几年里，我与同事们一起提供的这些见解的相关性，从其他研究人员认可我的工作并在其基础上发展而来的大量工作中可见一斑。事实上，我的研究影响超越了纯粹的量子信息理论，并已在宇宙学和黑洞物理的基础问题上找到了应用。我计划在研究员期间完成的研究旨在为相对论量子信息理论的基础、理论和技术方面提供全面的答案，开发和发展迄今取得的耐人寻味的成果。我的总体抱负和愿景是最终为量子信息理论领域的关键问题提供具体解决方案。

My research programme is the study of how relativistic effects can be exploited to improve quantum information tasks, a key topic of immense technological importance already today and more so for the next decades. The vantage point of these investigations is that the world is fundamentally both quantum and relativistic, and that these facts are immensely useful for the design of communication devices that are absolutely safe from eavesdropping, and of quantum computers that can quickly perform difficult computational tasks which overwhelm any classically imaginable computer. Indeed, impressive technological achievements and promises have already been derived from taking seriously solely the quantum aspects of matter: quantum cryptography and communication have become a technical reality in recent years, but the practical construction of a quantum computer still requires to understand better how to efficiently store, manipulate and read information, without prohibitively large disturbances from the environment. Throwing relativity into the equation fundamentally changes the entire game, as I could show in a series of research papers, one of which was featured in a generally accessible Science article highlighting my work (Cho, Science 2005). I propose to push this exciting line of theoretical research to the point where relativistic effects in quantum information theory can be exploited technologically.Far from yielding only quantitative corrections, relativity plays a dominant role in the qualitative behaviour of many physical systems used to implement quantum information tasks in the laboratory. The prototypical example is provided by any system involving light, be it for the transmission or manipulation of quantum information. There is no such thing as a non-relativistic approximation to light quanta, so-called photons, since these always travel at the speed of light. While relativistic quantum theory, commonly known as quantum field theory, is a very well studied subject in foundational particle physics, research in quantum information theory selectively focused almost exclusively on those aspects one can study without relativity. Thus both unexpected obstacles (such as a relativistic degradation of quantum entanglement) and unimagined possibilities for quantum information theory (such as improved quantum cryptography and hypersensitive quantum measurement devices) have gone unnoticed. The relevance of these insights, which together with co-workers, I afforded over the past few years, are evidenced by the amount of work by other researchers recognizing and building on my work. Indeed, the impact of my research extends beyond pure quantum information theory, and applications to foundational questions in cosmology and black hole physics have been found.The research I propose to complete during my Fellowship aims at providing comprehensive answers to foundational, theoretical and technological aspects of relativistic quantum information theory, exploiting and building on the intriguing results obtained so far. My overall aspiration and vision is to ultimately provide concrete solutions to key problems in the field of quantum information theory.