Quantum Information Processing: A Brief Overview of Recent Advances

Abstract

In the mid-1930s two influential but seemingly unrelated papers were published. In 1935, Einstein, Podolsky and Rosen proposed the famous EPR paradox that has come to symbolize the mysteries of quantum mechanics. Two years later, Alan Turing introduced the universal Turing machine and laid the foundations of the computer industry. Although quantum physics is essential to understanding the operation of transistors and other solid state devices in computers, computation itself has remained a resolutely classical process. Surely the uncertainty associated with quantum theory is seemingly not compatible with the reliability expected from computers. In 1982, Richard Feynman suggested that individual quantum systems could be used for computations. In 1985, David Deutsch from the University of Oxford described the universal quantum computer and showed that quantum theory can allow computers to do more rather than less. An important new observation is that information is not independent of the physical laws which govern the system used to store and process it (Landauer). On the atomic scale matter obeys the laws of quantum mechanics, which are quite different from the ones of classical physics that determine the characteristics of conventional computers. Therefore quantum computers will have qualitatively new properties and capabilities. During the past ten years scientific groups all over the world have worked to establish the theoretical foundations and to investigate different experimental realizations of quantum computing and quantum communications.