Information in quantum theory

Abstract

This chapter outlines the ‘engineering’ and ‘scientific’ approaches to the study of information in classical physics, and the fairly minor changes that came with the arrival of quantum theory in the early twentieth century. The main advances came from the mid-1990s when quantum information theory developed enormously, with important work, theoretical and experimental, carried out in quantum computation, quantum cryptography and quantum teleportation. The concept of information as the fundamental building-block of the Universe also became important, and also the idea that the Universe was a quantum computer.