EXPLOITING RELATIVITY FOR QUANTUM INFORMATION THEORY

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.