Quantum information - A tutorial

Abstract

Information processing, information transmission, and information security are everyday notions of modern society. But what exactly is information? This seems to be quite a hard question. Analogous complication arises in physical sciences when asking what exactly energy is. A naive approach to define information is to define information as a message contained in a string of symbols, but naturally enough, a similar question about the meaning of "message" arises. In this presentation all potential societal and qualitative connotations of information are stripped away and we will restrict only to the quantitative mathematical aspects of information. 20th century witnessed the birth of quantum mechanics, a novel theory establishing a united way to treat two apparently distinct aspects of microsystems: undulatory and corpuscular. Quantum mechanics did not only bring unification, but also severe philosophical problems on the nature of reality. © 2011 Springer-Verlag Berlin Heidelberg.