Since joining IBM Research in 1972, Charles Bennett has worked on various aspects of the relation between physics and information.
In 1973, building on the work of IBM’s Rolf Landauer, he showed that general-purpose computation can be performed by a logically and thermodynamically reversible apparatus, which can operate with arbitrarily little energy dissipation per step because it avoids throwing away information about past logical states.
In collaboration with Gilles Brassard of the University of Montreal, he developed a practical system of quantum cryptography, allowing secure communication between parties who share no secret information initially, based on the uncertainty principle instead of on usual computational assumptions such as the difficulty of factoring. In 1993 Bennett and Brassard, in collaboration with Claude Crepeau, Richard Jozsa, Asher Peres and William Wootters, discovered ‘quantum teleportation.’ This is an effect in which the complete information in an unknown quantum state is decomposed into purely classical information and purely non-classical Einstein-Podolsky-Rosen (EPR) correlations, sent through two separate channels, and later reassembled in a new location to produce an exact replica of the original quantum state that was destroyed in the sending process.
In 1995–97, working with Wootters, IBM’s David DiVincenzo and others, Bennett helped found the quantitative theory of entanglement, and introduced several techniques for faithful transmission of classical and quantum information through noisy channels – part of the larger and recently very active field of quantum information and computation theory. Recently, he has worked on the capacities for quantum channels and interactions to simulate one another, and the tradeoffs among communications resources.
Wolf Prize for Physics, 2018
Fellow of the American Physical Society
Member, National Academy of Sciences