Principles of quantum communications engineering

• Applicant: Dr. Janis Nötzel
• Subject Area: Electronic Semiconductors, Components and Circuits, Integrated Systems, Sensor Technology, Theoretical Electrical Engineering
• Term: from 2015 to 2016
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 270559638

One of the most fascinating developments of our time is the emergence of local, nation spanning and even global information processing systems which connect increasing numbers of sensors, individuals, companies and nations. Their economic potential and their impact on our society are enormous. We are also faced with their vulnerabilities, for example instabilities caused by attacks or changes in their environment or security problems. The technological potential enabling these changes has accumulated over decades, driven by factors like e.g. Moore s law. Of course, for continued validity of Moore s law, the average size per bit of information of the physical media which are being used for data storage has to decrease continuously. This makes it ultimately necessary to understand information processing at sub atomic scales, one of two points where quantum information processing comes into play as a key technology in modern engineering. The second point is secure communication: Research in quantum information theory led to completely new and unexpected results, and especially one of them triggered a wave of research: Shor s factoring algorithm, published in 1994. The groundbreaking news then was that factoring of large numbers was an easy task, once a quantum computer would be available. The importance of this result stems from the fact that today s standard encryption protocols like RSA rely on assumptions like the impossibility of factoring large numbers in reasonable time. But Shor s result should be seen in context with its counterpart: The promise of perfect security directly from the laws of quantum physics discovered by Bennett and Brassard in 1984. Today, the technological implementations of secure quantum communication lines are on their way, as well as a paradigm shift in the design of secure wireless systems that follows similar guidelines: From on-top solutions to embedded security, guaranteed by the laws of physics. With this project, we will contribute to the information theoretic foundation which is needed to understand and guarantee robust and secure information transmission. We will mostly consider quantum systems, but also hybrid or purely classical systems. We will analyze resources like (shared) randomness and feedback. A central goal of this project will be a joint treatment of security and stability for systems which are subject to changes during transmission, may they be caused by fluctuations in the environment s parameters or by active manipulation. We will also work on an information theoretic analysis of traditional machine learning tasks, which are intimately connected to robust communication. This will help to incorporate automated learning steps into future systems, together with the communication functionalities. Our results will help to quantify the theoretical limits of quantum communication systems. This is an important step in the formulation of design paradigms for future communication systems.

• DFG Programme: Research Fellowships
• International Connection: Spain
• Host: Professor Dr. Andreas Winter