Quantum effects in information processing, aside from making possible feats like quantum cryptography and Shor's factoring algorithm, have led to more coherent and powerful ways of thinking about information, computation, and cosmology. We review this approach, especially the uniquely private form of correlation known as entanglement, whose very pervasiveness makes it hard to detect, allowing it to remain undiscovered until the 20th century. In combination with thermal disequilbrium, entanglement helps us understand why the future is more uncertain than the past, and how our world produces structures that are logically "deep", having internal evidence of a complicated history, an idea that can be made precise using the tools of algorithmic information and computational complexity. Finally we consider the Boltzmann brain problem afflicting many modern cosmologies, where similar structures are predicted to fluctuate into existence even at thermal equilibrium, bearing false evidence of a complicated history that never happened.
Charles Bennett is a physicist, information theorist and IBM Fellow at IBM Research.
Bennett's work at IBM has concentrated on a re-examination of the physical basis of information, applying quantum physics to the problems
surrounding information exchange. He has played a major role in elucidating the interconnections between physics and information, particularly
in the realm of quantum computation, but also in cellular automata and reversible computing.
With Gilles Brassard, Bennett showed that privacy of communication can be guaranteed
by quantum laws ("quantum cryptography"), and with their students designed and
first working demonstration of it.
In 1993 Bennett and Brassard, in collaboration with Claude Crepeau, Richard Jozsa, Asher Peres, and William Wootters, discovered
and in 1995-7, working with Smolin, Wootters, IBM's David DiVincenzo, and other collaborators, he helped found the quantitative theory of entanglement.
Recently he has worked on the capacities for quantum channels and interactions to simulate one another and the trade-offs among communications resources.
Charles Bennett is a Fellow of the American Physical Society, and a member of the National Academy of Sciences.