What are the ultimate limits that nature imposes on communication and what are effective procedures for achieving these limits? In order to answer these questions convincingly, we must reassess the theory of information under a “quantum lens.” That is, since quantum mechanics represents our best understanding of microscopic physical phenomena and since information is ultimately encoded into a physical system of some form, it is necessary for us to revise the laws of information established many years ago by Shannon. This is not merely an academic exercise, but instead represents one of the most exciting new frontiers for physics, mathematics, computer science, and engineering. Entanglement, superposition, and interference are all aspects of quantum theory that were once regarded as strange and in some cases, nuisances. However, nowadays, we understand these phenomena to be features that are the enabling fuel for a new quantum theory of information, in which seemingly magical possibilities such as teleportation are becoming reality. Two other notable examples are increased communication capacities of noisy communication channels and secure encryption based on physical principles. Concepts developed in the context of quantum information theory are now influencing other areas of physics as well, such as quantum gravity, condensed matter, and thermodynamics. Furthermore, quantum information theory has given us a greater understanding of the foundations of quantum mechanics and might eventually lead to a simpler set of postulates for quantum mechanics. This tutorial will review the basics of quantum information, in an effort to enable those trained in the traditional formulation of information theory to have a grasp for what distinguishes quantum information theory from the traditional formulation. An outline is as follows:
Mark M. Wilde is an Associate Professor in the Department of Physics and Astronomy and the Center for Computation and Technology at Louisiana State University. He is a recipient of the Career Development Award from the US National Science Foundation, co-recipient of the 2018 AHP-Birkhauser Prize from the journal Annales Henri Poincare, and Associate Editor for Quantum Information Theory at IEEE Transactions on Information Theory and New Journal of Physics. His current research interests are in quantum Shannon theory, quantum optical communication, quantum computational complexity theory, and quantum error correction.
