Quantum Randomness: From Practice to Theory and Back

There is a huge demand for “random” bits. Random number generators use software or physical processes to produce “random” bits. While it is known that programs cannot produce high-quality randomness—their bits are pseudorandom—other methods claim to produce “true” or “perfect” random sequences. Such claims are made for quantum random generators, but, if true, can they be proved? This paper discusses this problem—which is important not only philosophically, but also from a practical point of view. 1 “Babylon Is Nothing but an Infinite Game of Chance” A mythical Babylon in which everything is dictated by a universal lottery is sketched in The Lottery in Babylon [8], a short story published in 1941 (first English translation in 1962) by Jorge Luis Borges. A normally operated lottery— with tickets, winners, losers, and money rewards—starts adding punishments to rewards and finally evolves into an all-encompassing “Company” whose decisions are mandatory for all but a small elite. The Company acts at random and in secrecy. Most Babylonians have two only options: to accept the all-knowing, all-powerful, but mysterious Company, or to deny its very existence (no such Company). While various possible philosophical interpretations of the story have been discussed, there is a large consensus that the Company symbolises the power and pervasiveness of randomness. Indeed, randomness is the very stuff of life, impinging on everything, fortunes and misfortunes, from the beginning to the end. It causes fear and anxiety, but also makes for fun; and, most interestingly, it provides efficient tools used since ancient Athens. C.S. Calude ( ) Department of Computer Science, University of Auckland, Private Bag 92019, Auckland, New Zealand e-mail: [email protected]; www.cs.auckland.ac.nz/~cristian © Springer International Publishing AG 2017 S.B. Cooper, M.I. Soskova (eds.), The Incomputable, Theory and Applications of Computability, DOI 10.1007/978-3-319-43669-2_11 169