Quantum Information Flow: A Computer Science Perspective

Quantum Information and Computation (QIC) is concerned with the use of quantum-mechanical systems to carry out computational and information-processing tasks [29]. It emerged from the recognition that quantum phenomena such as entanglement—Einstein’s “spooky action at a distance”— should be seen not as a bug but as a feature. Some first fruits of this were the Deutch-Jozsa, Shor and Grover algorithms, the BB84 and Ekert 91 public key distribution schemes, the quantum teleportation protocol and several variants [29]. However, although the point of view is new, the methods have largely remained traditional: the manipulations of complex numbers, vectors and matrices in “computational bases” built from kets |0〉 and |1〉 bear some comparison with the acrobatics with bits and bytes in the early days of computer programming.