Charles H. Bennett

Charles H. Bennett is an IBM Fellow at IBM Research. Bennett's recent 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. Image File history File links Charles_H_Bennett. ... Image File history File links Charles_H_Bennett. ... IBM Research, a subsidiary of IBM, has existed since 1945 and currently consists of eight locations throughout the world and hundreds of projects. ... A cellular automaton (plural: cellular automata) is a discrete model studied in computability theory and mathematics. ... The term reversible computing refers to any computational process that is (at least to some close approximation) reversible, i. ...

Born in 1943, he earned a B.S. in Chemistry from Brandeis University in 1964, and received his PhD from Harvard in 1970 for molecular dynamics studies (computer simulation of molecular motion) under David Turnbull and Berni Alder. For the next two years he continued this research under the late Aneesur Rahman at Argonne Laboratory. Brandeis University is a private university in Waltham, Massachusetts, United States. ... Harvard University is a private university in Cambridge, Massachusetts, USA, and a member of the Ivy League. ... David Turnbull (born March 17, 1942 in Newcastle upon Tyne, England) is a politician in Ontario, Canada. ... Argonne National Laboratory is one of the United States governments oldest and largest science and engineering research national laboratories and is the largest in the Midwest. ...

After joining IBM Research in 1972, he built on the work of IBM's Rolf Landauer to show that general-purpose computation can be performed by a logically and thermodynamically reversible apparatus; and in 1982 he proposed a re-interpretation of Maxwell's demon, attributing its inability to break the second law to the thermodynamic cost of destroying, rather than acquiring, information. Rolf Landauer (1927 – 1999) was an IBM physicist who in 1961 demonstrated that when information is lost in an irreversible circuit, the information becomes entropy and an associated amount of energy is dissipated as heat. ... Maxwells demon is a character in an 1867 thought experiment by the Scottish physicist James Clerk Maxwell, meant to raise questions about the possibility of violating the second law of thermodynamics. ... Thermodynamics (from the Greek thermos meaning heat and dynamics meaning power) is a branch of physics that studies the effects of changes in temperature, pressure, and volume on physical systems at the macroscopic scale by analyzing the collective motion of their particles using statistics. ...

In collaboration with Gilles Brassard of the University of Montreal he developed a practical system of quantum cryptography, known as BB84, which allows secure communication between parties who share no secret information initially, based on the uncertainty principle. With the help of John Smolin, he built the world's first working demonstration of quantum cryptography in 1989. Gilles Brassard was born in Montréal, Canada, in 1955. ... Quantum cryptography is an approach based on quantum physics for secure communications. ... BB84 is a quantum key distribution scheme developed by Charles Bennett and Gilles Brassard in 1984. ...

His other research interests include algorithmic information theory, in which the concepts of information and randomness are developed in terms of the input/output relation of universal computers, and the analogous use of universal computers to define the intrinsic complexity or "logical depth" of a physical state as the time required by a universal computer to simulate the evolution of the state from a random initial state.

In 1993 Bennett and Brassard, in collaboration with others, discovered "quantum teleportation", 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 paradox) 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 quantum information, quantum teleportation, or entanglement-assisted teleportation is a technique that transfers a quantum state to an arbitrarily distant location using a distributed entangled state and the transmission of some classical information. ... In quantum mechanics, the EPR paradox (Einstein-Podolsky-Rosen) is a thought experiment which challenged long-held ideas about the relation between, on the one hand the observed values of physical quantities and on the other, the values that can be accounted for by a physical theory. ...

In 1995-7, working with Smolin, Wootters, IBM's David DiVincenzo, and other collaborators, he 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. He is an IBM Fellow, a Fellow of the American Physical Society, and a member of the National Academy of Sciences.

References

• Charles Bennett's page at IBM site
• List of publications