Charles Henry Bennett (born 1943) is a

physicist A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate cau ...

information theorist Information is an abstract concept that refers to something which has the power to inform. At the most fundamental level, it pertains to the interpretation (perhaps formally) of that which may be sensed, or their abstractions. Any natur ...

and

IBM Fellow An IBM Fellow is a position at IBM appointed by the CEO. Typically only four to nine (eleven in 2014) IBM Fellows are appointed each year, in May or June. Fellow is the highest honor a scientist, engineer, or programmer at IBM can achieve. Over ...

IBM Research IBM Research is the research and development division for IBM, an American Multinational corporation, multinational information technology company. IBM Research is headquartered at the Thomas J. Watson Research Center in Yorktown Heights, New York ...

. Bennett's recent work at IBM has concentrated on a re-examination of the physical basis of information, applying

quantum physics Quantum mechanics is the fundamental physical Scientific theory, theory that describes the behavior of matter and of light; its unusual characteristics typically occur at and below the scale of atoms. Reprinted, Addison-Wesley, 1989, It is ...

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 A quantum computer is a computer that exploits quantum mechanical phenomena. On small scales, physical matter exhibits properties of both particles and waves, and quantum computing takes advantage of this behavior using specialized hardware. C ...

, but also in

cellular automata A cellular automaton (pl. cellular automata, abbrev. CA) is a discrete model of computation studied in automata theory. Cellular automata are also called cellular spaces, tessellation automata, homogeneous structures, cellular structures, tessel ...

and

reversible computing Reversible computing is any model of computation where every step of the process is time-reversible. This means that, given the output of a computation, it's possible to perfectly reconstruct the input. In systems that progress deterministica ...

. He discovered, with

Gilles Brassard Gilles Brassard is a faculty member of the Université de Montréal, where he has been a Full Professor since 1988 and Canada Research Chair since 2001. Education and early life Brassard received a Ph.D. in Computer Science from Cornell Univers ...

, the concept of

quantum cryptography Quantum cryptography is the science of exploiting quantum mechanical properties to perform cryptographic tasks. The best known example of quantum cryptography is quantum key distribution, which offers an information-theoretically secure soluti ...

and is one of the founding fathers of modern

quantum information theory Quantum information is the information of the state of a quantum system. It is the basic entity of study in quantum information theory, and can be manipulated using quantum information processing techniques. Quantum information refers to both t ...

(see Bennett's four laws of quantum information).

Early career

Born in 1943 in New York City, Bennett earned a B.S. in chemistry from

Brandeis University Brandeis University () is a Private university, private research university in Waltham, Massachusetts, United States. It is located within the Greater Boston area. Founded in 1948 as a nonsectarian, non-sectarian, coeducational university, Bra ...

in 1964 and received his PhD from

Harvard Harvard University is a private Ivy League research university in Cambridge, Massachusetts, United States. Founded in 1636 and named for its first benefactor, the Puritan clergyman John Harvard, it is the oldest institution of higher lear ...

in 1970 for molecular-dynamics studies (computer simulation of molecular motion) under David Turnbull and

Berni Alder Berni Julian Alder (September 9, 1925 – September 7, 2020) was a German-born American physicist specialized in statistical mechanics, and a pioneer of computational modelling of matter. Biography Alder was born in Duisburg, Prussia, in Septem ...

. At Harvard, he also worked for

James Watson James Dewey Watson (born April 6, 1928) is an American molecular biology, molecular biologist, geneticist, and zoologist. In 1953, he co-authored with Francis Crick the academic paper in ''Nature (journal), Nature'' proposing the Nucleic acid ...

one year as a teaching assistant about the genetic code. For the next two years he continued this research under

Aneesur Rahman Aneesur Rahman (24 August 1927 – 6 June 1987) was an Indian-born American physicist who pioneered the application of computational methods to physical systems. His 1964 paper on liquid argon studied a system of 864 argon atoms on a CDC 3600 ...

Argonne National Laboratory Argonne National Laboratory is a Federally funded research and development centers, federally funded research and development center in Lemont, Illinois, Lemont, Illinois, United States. Founded in 1946, the laboratory is owned by the United Sta ...

(operated by the

University of Chicago The University of Chicago (UChicago, Chicago, or UChi) is a Private university, private research university in Chicago, Illinois, United States. Its main campus is in the Hyde Park, Chicago, Hyde Park neighborhood on Chicago's South Side, Chic ...

). After joining IBM Research in 1972, he built on the work of IBM's

Rolf Landauer Rolf William Landauer (February 4, 1927 – April 27, 1999) was a German American, German-American physicist who made important contributions in diverse areas of the thermodynamics of information processing, condensed matter physics, and the cond ...

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 Maxwell's demon is a thought experiment that appears to disprove the second law of thermodynamics. It was proposed by the physicist James Clerk Maxwell in 1867. In his first letter, Maxwell referred to the entity as a "finite being" or a "being ...

, attributing its inability to break the second law to the

thermodynamic Thermodynamics is a branch of physics that deals with heat, work, and temperature, and their relation to energy, entropy, and the physical properties of matter and radiation. The behavior of these quantities is governed by the four laws of th ...

cost of destroying, rather than acquiring, information. He also published an important paper on the estimation of free-energy differences between two systems, the

Bennett acceptance ratio The Bennett acceptance ratio method (BAR) is an algorithm for estimating the difference in free energy between two systems (usually the systems will be simulated on the computer). It was suggested by Charles H. Bennett in 1976. Preliminaries Tak ...

method.

Quantum cryptography

In collaboration with

of the

Université de Montréal The Université de Montréal (; UdeM; ) is a French-language public research university in Montreal, Quebec, Canada. The university's main campus is located in the Côte-des-Neiges neighborhood of Côte-des-Neiges–Notre-Dame-de-Grâce on M ...

, Bennett developed a system of

, building on an idea of

Stephen Wiesner Stephen J. Wiesner (1942 – August 12, 2021) was an American-Israeli research physicist, inventor and construction laborer. As a graduate student at Columbia University in New York in the late 1960s and early 1970s, he discovered several of the ...

. Known as

BB84 BB84 is a quantum key distribution scheme developed by Charles Bennett and Gilles Brassard in 1984. It is the first quantum cryptography protocol. The protocol is provably secure assuming a perfect implementation, relying on two conditions: (1) t ...

, the system takes advantage of the

uncertainty principle The uncertainty principle, also known as Heisenberg's indeterminacy principle, is a fundamental concept in quantum mechanics. It states that there is a limit to the precision with which certain pairs of physical properties, such as position a ...

to allow secure communication between parties who share no secret information initially. With the help of John Smolin, he built the world's first working demonstration of quantum cryptography in 1989. 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.

Teleportation

In 1993 Bennett and Brassard, in collaboration with others, discovered "

quantum teleportation Quantum teleportation is a technique for transferring quantum information from a sender at one location to a receiver some distance away. While teleportation is commonly portrayed in science fiction as a means to transfer physical objects from on ...

", 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 EPR may refer to: Science and technology * EPR (nuclear reactor), European Pressurised-Water Reactor * EPR paradox (Einstein–Podolsky–Rosen paradox), in physics * Earth potential rise, in electrical engineering * East Pacific Rise, a mid-ocea ...

) correlations, sent through two separate channels, and later reassembled in a new location to produce an exact replica of the original

quantum state In quantum physics, a quantum state is a mathematical entity that embodies the knowledge of a quantum system. Quantum mechanics specifies the construction, evolution, and measurement of a quantum state. The result is a prediction for the system ...

that was destroyed in the sending process.

Later work

In 1995–1997, working with Smolin, Wootters, DiVincenzo, and other collaborators, he introduced several techniques for faithful transmission of classical and quantum information through noisy channels, part of the larger field of quantum information and computation theory. Together with others he also introduced the concept of

entanglement distillation Entanglement distillation (also called entanglement purification) is the transformation of ''N'' copies of an arbitrary Quantum entanglement, entangled state \rho into some number of approximately pure Bell pairs, using only LOCC, local operation ...

. Bennett is a Fellow of the

American Physical Society The American Physical Society (APS) is a not-for-profit membership organization of professionals in physics and related disciplines, comprising nearly fifty divisions, sections, and other units. Its mission is the advancement and diffusion of ...

and a member of the

National Academy of Sciences The National Academy of Sciences (NAS) is a United States nonprofit, NGO, non-governmental organization. NAS is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy of Engineering (NAE) and the ...

. He was awarded the 2008

Harvey Prize The Harvey Prize is an annual Israeli award for breakthroughs in science and technology, as well as contributions to peace in the Middle East granted by the Technion – Israel Institute of Technology, Technion in Haifa. The prize has become a ...

by the Technion and the 2006 Rank Prize in opto-electronics. In 2017 he received the

Dirac Medal The Dirac Medal or Dirac prize can refer to different awards named in honour of the physics Nobel Laureate Paul Dirac. * Dirac Medal (ICTP), awarded by the Abdus Salam International Centre for Theoretical Physics, Trieste * Dirac Medal (IOP), awar ...

of the

ICTP The Abdus Salam International Centre for Theoretical Physics (ICTP) is a research center for physical and mathematical sciences, located in Trieste, Friuli-Venezia Giulia, Italy. The center operates under a tripartite agreement between the It ...

and in 2018 the

Wolf Prize in Physics The Wolf Prize in Physics is awarded once a year by the Wolf Foundation in Israel. It is one of the six Wolf Prizes established by the Foundation and awarded since 1978; the others are in Agriculture, Chemistry, Mathematics, Medicine and Arts. The ...

. In June 2019, he received the

Shannon Award The Claude E. Shannon Award of the IEEE Information Theory Society was created to honor consistent and profound contributions to the field of information theory. Each Shannon Award winner is expected to present a Shannon Lecture at the following ...

and for 2019 the

BBVA Foundation Frontiers of Knowledge Award The BBVA Foundation Frontiers of Knowledge Awards () are an international award programme recognizing significant contributions in the areas of scientific research and cultural creation. The categories that make up the Frontiers of Knowledge Awards ...

in Basic Sciences. In 2023 he was awarded the

Breakthrough Prize in Fundamental Physics The Breakthrough Prize in Fundamental Physics is one of the Breakthrough Prizes, awarded by the Breakthrough Prize Board. Initially named Fundamental Physics Prize, it was founded in July 2012 by Russia-born Israeli entrepreneur, venture capit ...

and also in 2023 the Eduard Rhein Foundation Prize in Technology. Bennett also co-runs a blog, ''The Quantum Pontiff'', with Steve Flammia and Aram Harrow and hosted by Dave Bacon.

Private life

Bennett identifies himself as an atheist. Recalling a fond memory of the physicist

Asher Peres Asher Peres (; January 30, 1934 – January 1, 2005) was an Israeli physicist. Peres is best known for his work relating quantum mechanics and information theory. He helped to develop the Peres–Horodecki criterion for quantum entanglement, as w ...

, he writes:Charles H. Bennett's letter written to the family of Israeli physicist Asher Peres, fro
a selection of the many letters of condolence sent to the Peres family during January 2005

References

External links

Charles Bennett's page at IBM site

''The Quantum Pontiff'' blog
{{DEFAULTSORT:Bennett, Charles H. American theoretical physicists 1943 births Living people Fellows of the American Physical Society Members of the United States National Academy of Sciences IBM Fellows IBM Research computer scientists Brandeis University alumni Harvard University alumni American atheists Scientists from New York City 20th-century American engineers 21st-century American engineers 20th-century American physicists 21st-century American physicists Science bloggers 21st-century science writers American quantum information scientists Wolf Prize in Physics laureates