Charles H. Bennett  Charles H. Bennett photo         

contact information

IBM Fellow
Thomas J. Watson Research Center, Yorktown Heights, NY USA


Vitae: Charles H. Bennett (12//2021)
Address: IBM T. J. Watson Research Center, PO Box 218, Yorktown Heights, NY 10598
Phone: +1-914- 945-3118, mobile +1-914-224-5225

Web Page:

Education: Ph.D., Chemical Physics, Harvard University (1971)
BA, Brandeis University, Chemistry, summa cum laude (1964)

1973-present Research Staff and IBM Fellow, IBM Research Division
1991 Fairchild Scholar at California Inst. of Technology
1986-1987 Visiting Scientist at MIT Lab for Computer Science
1984-1986 Visiting Professor, Boston U. CS Department
1972-1973 Postdoctoral Fellow, IBM Watson Research Center
1971-1972 Postdoctoral Fellow, Argonne National Laboratory

Awards: Rank 2006, Harvey 2009, Okawa 2011, ICTP Dirac Medal 2017,
Wolf 2018, Micius Quantum Prize 2019, Shannon Lecture 2020, BBVA Frontiers of Knowledge 2020

IBM Academy of Technology 1992,  IBM Fellow 1995

National Academy of Sciences 1997
American Physical Society Fellow
Danish Royal Academy of Sciences and Arts 2019
Honorary doctorates: Masaryk U., U. of Gdansk, U. of Bristol, ETH-Zurich, Copenhagen University

Research Interests: Physics of information processing, including:
• Thermodynamics of computation, error-correction and fault-tolerance
• Theory of entanglement, quantum channels and quantum cryptography;
• Physically-based cryptography and authentication;
• Algorithmic information theory and computational complexity in physics
• Decoherence and emergence of classical world from quantum laws
• Quantum and algorithmic approaches to fundamental questions in cosmology

Professional Activities
• Divisional Associate Editor of Physical Review Letters for quantum information (1999-2003)
• Steering committee of annual Quantum Information Processing (QIP) conference (2002-3), and Asian Quantum Information Science (AQIS) conference 
• Co-organizer of Isaac Newton Institute program on Quantum Information (Cambridge, UK, 2004)
• Canadian Institute for Advanced Research (CIFAR) Advisory committee on Quantum Information processing 2007-2019
• Offices in US National Academy of Sciences (NAS) 2006-2009, Secretary of Engineering and Applied Physical Sciences (Class III) in NAS 2012-2014 and 2018-2021, Chair of Class III, 2014-2017
• American Physical Society Council Representative for Division of Quantum Information and  Council Steering Committee member (2019-2021)

International Experience and Outreach:
• Gave tutorial lecture series at first major quantum information conference in India at Tata Institute for Fundamental Research (TIFR) Mumbai 2002 and a similar early lecture series at Pan American Studies Institute, Buzios, Brazil 2003.
• Longtime service on steering committee of AQIS (Asian Quantum Information Science), Program Committee co-chair 2012
• Lectures at Indian Institute of Technology (IIT) campuses in Mumbai, Kanpur, Kharagpur, Madras, and at Institute of Physics (Bhubaneswar ), Indian Statistical Institute (Kolkata), and C.V. Raman Institute (Bangalore), Techfest 2011, an India-wide event organized by students at IIT, BombayHarish-Chandra Research Institute (Allahabad)
• Visits to IBM Laboratories in Zurich, Tokyo, Pune, Bangalore, Delhi, Santiago Chile. Many other international scientific visits and lectures in Japan, South Korea, China, Canada, Denmark, UK, France, Germany, Belgium, Italy, Israel, Austria, Spain, Sweden, Poland, Czech Republic, Switzerland, Brazil, Chile, Hong Kong, Singapore, South Africa, Malaysia, and Egypt
• Co-organized workshop Quantum Origins of a Classical Universe at IBM Research Yorktown Heights NY, 2014
• Taught course on Physics of Oblivion at Chautauqua Institution, NY, 2015
• Co-organized Simons workshop Quantum Information in Cosmology at Niels Bohr International Academy April 8-12, 2018

------------------Selected Publications (annotated)--------------------

Charles H. Bennett, Igor Devetak, Aram W. Harrow, Peter W. Shor, and Andreas Winter, "The quantum reverse Shannon theorem and resource tradeoffs for simulating quantum channels," IEEE Trans. Inf. Theory 60, 5:2926-2959 (2014).
Extends 2002 IEEE paper on classical reverse Shannon theorem, showing that quantum channels of equal entanglement-assisted capacity can simulate one another efficiently in the presence of shared entanglement, but sometimes this requires special forms of entanglement, e.g. "entanglement-embezzling states" or additional resources such as classical back-communication.

Charles H. Bennett, Debbie Leung, Graeme Smith, John A. Smolin
“Can closed timelike curves or nonlinear quantum mechanics improve quantum state discrimination or help solve hard problems?” Phys.Rev.Lett.103:170502, (2009) (argued that nonlinear extensions of quantum mechanics, such as the widely used Deutsch model of closed timelike curves, do not improve state-discrimination and have not been shown to speed up computation.)

C.H. Bennett, “Publicity, Privacy and Permanence of Information,” in APS
Proceedings of Quantum Information Back-Action Conference, Kanpur, India (2006)
(argued that most classical information originating on earth, e.g. the pattern of sand grains on a beach, is eventually lost in thermal radiation from the earth, becoming terrestrially inaccessible in principle)

C.H. Bennett, I. Devetak, P.W. Shor, J.A. Smolin,
“Inequalities and Separations among Assisted Capacities of Quantum Channels” Phys. Rev. Lett. 96.150502 (2006) (auxiliary resources, like shared entanglement or back communication, which do not increase the capacity of classical channels, generally increase that of quantum channels. Entanglement is the strongest auxiliary resource, giving the largest assisted capacity, and the one most analogous to the single capacity of classical channels.)

Charles H. Bennett, Ming Li, and Bin Ma, "Chain Letters and Evolutionary Histories",
Scientific American 288:6, 76-81 (2003) (popular article documenting pre-Internet evolution of phtotcopied chain letters with analogies to biological evolution)

Charles H. Bennett; Peter W. Shor, John A. Smolin, and Ashish V. Thapliyal
"Entanglement-assisted capacity of a quantum channel and the reverse Shannon theorem", IEEE Trans. Info. Theory 48, 2637-2655 (2002); quant-ph/0106052. (gave simple formula for entanglement assisted capacity of quantum channels and shows that, with the assistance of shared randomness between sender and receiver, noiseless classical channels can simulate noisy ones of equal capacity with unit efficiency in the limit of large block size. )

C.H. Bennett, E. Bernstein, G. Brassard, and U. Vazirani
"Strengths and Weaknesses of Quantum Computing,"
SIAM J. Comput. 26, 1510-1523 (1997) (In a converse to Grover’s algorithm, showed that quantum computers can speed up searches against a black box oracle no more than quadratically, dampening earlier hopes for a exponential speedup of NP-type problems)

C.H. Bennett, D.P. DiVincenzo, J.A. Smolin, and W.K. Wootters, "Mixed State Entanglement and Quantum Error Correction" Phys. Rev. A 54, 3824 (1996) eprint quant-ph/9604024 . (The 5-qubit code and the relation of quantum error correcting codes to entanglement distillation (then called purification); multiple capacities for quantum channels)

C. H. Bennett, G. Brassard, S. Popescu, J. A. Smolin, and W. K. Wootters,
"Purification of noisy entanglement and faithful teleportation via noisy channels,"
Phys. Rev. Lett. 76, 722 (1996). (Introduced entanglement distillation protocols for mixed entangled states, allowing quantum information to be sent reliably over a noisy channel).

C. H. Bennett, H. Bernstein, S. Popescu, and B. Schumacher, "Concentrating entanglement by local operations," Phys. Rev. A 53, 2046 (1996). ("Entanglement gambling", and efficient asymptotic interconveribilty of pure entangled states)

C. H. Bennett, G. Brassard, C. Crepeau, R. Jozsa, A. Peres, and W.K. Wootters, "Teleporting an unknown quantum state via dual classical and Einstein Podolsky Rosen channels," Phys. Rev. Lett. 70, 1895 (1993). (introduced quantum teleportation)

Charles H. Bennett and Stephen J. Wiesner, "Communication via 1- and 2-Particle Operators on Einstein-Podolsky- Rosen States" Phys. Rev. Lett. 69, 2881-2884 (1992) (introduced superdense coding, whereby 2 bits can be sent via a single qubit, provided it was previously entangled with another qubit held by the receiver. First paper on entanglement-assisted communication.)

Charles H. Bennett, "Quantum Cryptography Using any Two Nonorthogonal States," Phys. Rev. Lett. 68, 3121-3124 (1992). (showed that even the simplest nontrivial set of quantum states can be used for quantum cryptography)

Charles H. Bennett, Francois Bessette, Gilles Brassard, Louis Salvail, and John Smolin, "Experimental Quantum Cryptography," J. of Cryptology 5, 3 (1992) (First experimental demonstration of quantum key distribution via the BB84 protocol)

Charles H. Bennett "Time/Space Trade-offs for Reversible Computation" S.I.A.M. Journal on Computing 18, 766-776 (1989). (efficient reversible simulation of irreversible computations)

Charles H. Bennett "Logical Depth and Physical Complexity" in The Universal Turing Machine-- a Half-Century Survey, edited by Rolf Herken Oxford University Press 227-257, (1988). (Characterization of physical systems' complexity in terms of algorithmic information and space/time complexity, a complex or "logically deep" object being one not rapidly computable from an algorithmically random description)

Charles H. Bennett, Gilles Brassard, and Jean-Marc Robert
"Privacy Amplification by Public Discussion"
S.I.A.M. Journal on Computing 17, 210-229 (1988)
(Introduced the technique of privacy amplification, whereby two parties sharing partly secret information can distill a smaller body of almost perfectly secret information by a public discussion under the nose of their adversary)

C.H. Bennett and G. Grinstein "On the Role of Dissipation in Stabilizing Complex and Nonergodic Behavior in Locally Interacting DiscreteSystems" Phys. Rev.Lett. 55, pp 657-660 (1985).
(Relation of thermodynamic irreversibility to a physical system's ability to exhibit nonergodicity on a set of positive measure in parameter space, as illustrated by the Toom model)

C.H. Bennett and G. Brassard "Quantum Cryptography: Public Key Distribution and Coin Tossing", Proceedings of IEEE International Conference on Computers Systems and Signal Processing, Bangalore India, Dec.1984, pp 175-179.
(Introduced quantum key distribution, via the "BB84" protocol, and how to use entanglement to defeat an otherwise secure quantum protocol for bit commitment. Many years later, Mayers generalized this to show that secure bit commitment is impossible. )

C.H. Bennett "The Thermodynamics of Computation-- a Review"
Internat. J. Theoret. Phys. 21905-940 (1982).
(showed that general purpose computation can be performed by a logically and thermodynamically reversible apparatus; proposed currently accepted resolution of Maxwell's Demon problem)

C.H. Bennett and J. Gill, "Relative to a Random Oracle A, P(A) is not equal to NP(A) is not equal to co-NP(A) with Probability 1," S.I.A.M. Journal on Computing, 10, pp. 96-113 (1981).
(Showed that many open problems in complexity theory have definite answers when relativized to a random oracle. Makes the conjecture, later refuted, that all theorems true relative to a random oracle are true absolutely (this does not hold, for example, for IP=PSPACE)).

C.H. Bennett "Dissipation-Error Tradeoff in Proofreading" BioSystems 11, 85-91 (1979)
(Characterized the thermodynamics of error-correction in an elementary model based on the chemistry of DNA replication with errors, with and without proofreading. Showed that even without proofreading the tradeoff is complex, including a regime in which the copying goes spontaneously forward, against an opposing external driving force, driven by the entropy of incorporated errors.)

C.H. Bennett "Efficient estimation of free energy differences from Monte Carlo data" J. Comp. Phys. 22, 245-268 (1976) (Introduced a now-standard technique for estimating free energy differences from samples of two canonical ensembles on the same configuration space)