John Hopfield Explained

John Hopfield
Birth Name:John Joseph Hopfield
Birth Date:15 July 1933
Birth Place:Chicago, Illinois, U.S.
Field:Physics
Molecular biology
Complex systems
Neuroscience
Work Institution:Bell Labs
Princeton University
University of California, Berkeley
California Institute of Technology
Education:Swarthmore College (AB)
Cornell University (PhD)
Doctoral Advisor:Albert Overhauser
Doctoral Students:Steven Girvin
Gerald Mahan
Bertrand Halperin
David J. C. MacKay
José Onuchic
Terry Sejnowski
Erik Winfree
Li Zhaoping
Thesis Title:A quantum-mechanical theory of the contribution of excitons to the complex dielectric constant of crystals
Thesis Url:https://www.proquest.com/docview/301894791/
Thesis Year:1958
Known For:Hopfield network
Modern Hopfield network
Hopfield dielectric
Polariton
Kinetic proofreading

John Joseph Hopfield (born July 15, 1933)[1] is an American physicist and emeritus professor of Princeton University, most widely known for his study of associative neural networks in 1982. He is known for the development of the Hopfield network. Previous to its invention, research in artificial intelligence (AI) was in a decay period or AI winter, Hopfield work revitalized large scale interest in this field.

In 2024 Hopfield, along with Geoffrey Hinton, was awarded the Nobel Prize in Physics for their foundational contributions to machine learning, particularly through their work on artificial neural networks.[2] He has been awarded various major physics awards for his work in multidisciplinary fields including condensed matter physics, statistical physics and biophysics.

Biography

Early life and education

John Joseph Hopfield was born in 1933 in Chicago to physicists John Joseph Hopfield (born in Poland as Jan Józef Chmielewski) and Helen Hopfield (née Staff).[3] [4]

Hopfield received a Bachelor of Arts with a major in physics from Swarthmore College in Pennsylvania in 1954 and a Doctor of Philosophy in physics from Cornell University in 1958. His doctoral dissertation was titled "A quantum-mechanical theory of the contribution of excitons to the complex dielectric constant of crystals". His doctoral advisor was Albert Overhauser.

Career

He spent two years in the theory group at Bell Laboratories working on optical properties of semiconductors working with David Gilbert Thomas[5] and later on a quantitative model to describe the cooperative behavior of hemoglobin in collaboration with Robert G. Shulman.[6] Subsequently he became a faculty member at University of California, Berkeley (physics, 1961–1964), Princeton University (physics, 1964–1980), California Institute of Technology (Caltech, chemistry and biology, 1980–1997) and again at Princeton (1997–),[1] where he is the Howard A. Prior Professor of Molecular Biology, emeritus.[7]

In 1976, he participated in a science short film on the structure of the hemoglobin, featuring Linus Pauling.[8]

From 1981 to 1983 Richard Feynman, Carver Mead and Hopfield gave a one-year course at Caltech called "The Physics of Computation".[9] [10] This collaboration inspired the Computation and Neural Systems PhD program at Caltech in 1986, co-founded by Hopfield.[11]

His former PhD students include Gerald Mahan (PhD in 1964),[12] Bertrand Halperin (1965), Steven Girvin (1977), Terry Sejnowski (1978), Erik Winfree (1998), José Onuchic (1987), Li Zhaoping (1990)[13] and David J. C. MacKay (1992).

Work

In his doctoral work of 1958, he wrote on the interaction of excitons in crystals, coining the term polariton for a quasiparticle that appears in solid-state physics.[14] [15] He wrote: "The polarization field 'particles' analogous to photons will be called 'polaritons'." His polariton model is sometimes known as the Hopfield dielectric.[16]

From 1959 to 1963, Hopfield and David G. Thomas investigated the exciton structure of cadmium sulfide from its reflection spectra. Their experiments and theoretical models allowed to understand the optical spectroscopy of II-VI semiconductor compounds.[17]

Condensed matter physicist Philip W. Anderson reported that John Hopfield was his "hidden collaborator" for his 1961–1970 works on the Anderson impurity model which explained the Kondo effect. Hopfield was not included as a co-author in the papers but Anderson admitted the importance of Hopfield's contribution in various of his writings.[18]

William C. Topp and Hopfield introduced the concept of norm-conserving pseudopotentials in 1973.[19] [20] [21]

In 1974 he introduced a mechanism for error correction in biochemical reactions known as kinetic proofreading to explain the accuracy of DNA replication.[22] [23]

Hopfield published his first paper in neuroscience in 1982, titled "Neural networks and physical systems with emergent collective computational abilities" where he introduced what is now known as Hopfield network, a type of artificial network that can serve as a content-addressable memory, made of binary neurons that can be 'on' or 'off'.[24] He extended his formalism to continuous activation functions in 1984.[25] The 1982 and 1984 papers represent his two most cited works. Hopfield has said that the inspiration came from his knowledge of spin glasses from his collaborations with P. W. Anderson.[26]

Together with David W. Tank, Hopfield developed a method in 1985–1986[27] [28] for solving discrete optimization problems based on the continuous-time dynamics using a Hopfield network with continuous activation function. The optimization problem was encoded in the interaction parameters (weights) of the network. The effective temperature of the analog system was gradually decreased, as in global optimization with simulated annealing.[29]

Hopfield is one of the pioneers of the critical brain hypothesis, he was the first to link neural networks with self-organized criticality in reference to the Olami–Feder–Christensen model for earthquakes in 1994.[30] [31] In 1995, Hopfield and Andreas V. Herz showed that avalanches in neural activity follow power law distribution associated to earthquakes.[32] [33]

The original Hopfield networks had a limited memory, this problem was addressed by Hopfield and Dimitry Krotov in 2016.[34] Large memory storage Hopfield networks are now known as modern Hopfield networks.[35]

Views on artificial intelligence

In March 2023, Hopfield signed an open letter titled "Pause Giant AI Experiments", calling for a pause on the training of artificial intelligence (AI) systems more powerful than GPT-4. The letter, signed by over 30,000 individuals including AI researchers Yoshua Bengio and Stuart Russell, cited risks such as human obsolescence and society-wide loss of control.[36] [37]

Upon being jointly awarded the 2024 Nobel Prize in Physics, Hopfield revealed he was very unnerved by recent advances in AI capabilities, and said "as a physicist, I'm very unnerved by something which has no control".[38] In a followup press conference in Princeton University, Hopfield compared AI with discovery of nuclear fission, which led to nuclear weapons and nuclear power.

Awards and honors

Hopfield received a Sloan Research Fellowship[39] in 1962 and as his father, he received a Guggenheim Fellowship (1968).[40] Hopfield was elected as a member of the American Physical Society (APS) in 1969,[41] [42] a member of the National Academy of Sciences in 1973, a member of the American Academy of Arts and Sciences in 1975, and a member of the American Philosophical Society in 1988.[43] [44] [45] He was the President of the APS in 2006.[46]

In 1969 Hopfield and David Gilbert Thomas were awarded the Oliver E. Buckley Prize of condensed matter physics by the APS "for their joint work combining theory and experiment which has advanced the understanding of the interaction of light with solids".[47]

In 1983 he was awarded the MacArthur Foundational Prize by the MacArthur Fellows Program.[48] In 1985, Hopfield received the Golden Plate Award of the American Academy of Achievement[49] and the Max Delbruck Prize in Biophysics by the APS. In 1988, he received the Michelson–Morley Award by Case Western Reserve University.[50] Hopfield received the Neural Networks Pioneer Award in 1997 by the Institute of Electrical and Electronics Engineers (IEEE).[51]

He was awarded the Dirac Medal of the International Centre for Theoretical Physics in 2001 "for important contributions in an impressively broad spectrum of scientific subjects"[52] [53] including "an entirely different [collective] organizing principle in olfaction" and "a new principle in which neural function can take advantage of the temporal structure of the 'spiking' interneural communication".

Hopfield received the Harold Pender Award in 2002 for his accomplishments in computational neuroscience and neural engineering from the Moore School of Electrical Engineering, University of Pennsylvania.[54] He received the Albert Einstein World Award of Science in 2005 in the field of life sciences.[55] In 2007, he gave the Fritz London Memorial Lecture at Duke University, titled "How Do We Think So Fast? From Neurons to Brain Computation".[56] Hopfield received the IEEE Frank Rosenblatt Award in 2009 for his contributions in understanding information processing in biological systems.[57] In 2012 he was awarded the Swartz Prize by the Society for Neuroscience.[58] In 2019 he was awarded the Benjamin Franklin Medal in Physics by the Franklin Institute,[59] and in 2022 he shared the Boltzmann Medal award in statistical physics with Deepak Dhar.[60]

He was jointly awarded the 2024 Nobel Prize in Physics with Geoffrey E. Hinton for "foundational discoveries and inventions that enable machine learning with artificial neural networks".[61] [62]

External links

Notes and References

  1. Web site: Hopfield, John J. . October 8, 2024 . Physics History Network American Institute of Physics.
  2. Web site: Press release: The Nobel Prize in Physics 2024 . October 8, 2024 . NobelPrize.org . en-US . October 8, 2024 . https://web.archive.org/web/20241008150403/https://www.nobelprize.org/prizes/physics/2024/press-release/ . live .
  3. Book: Lindsay, Grace . Models of the Mind: How Physics, Engineering and Mathematics Have Shaped Our Understanding of the Brain . March 4, 2021 . Bloomsbury Publishing . 978-1-4729-6645-2 . en . October 8, 2024 . October 8, 2024 . https://web.archive.org/web/20241008150358/https://books.google.com/books?id=ieYdEAAAQBAJ&dq=john+hopfield+biography&pg=PA90 . live .
  4. Web site: American Men of Science: A Biographical Directory . 3 . Science Press . 1966 .
  5. Book: Orton, John W. . The Story of Semiconductors . December 11, 2008 . OUP Oxford . 978-0-19-156544-1 . en.
  6. March 1, 1985 . American Physical Society Meets in Baltimore . Physics Today . en . 38 . 3 . 87–93 . 10.1063/1.2814495 . 1985PhT....38c..87. . 0031-9228.
  7. Web site: Office of Communications . October 8, 2024 . Princeton's John Hopfield receives Nobel Prize in physics . October 8, 2024 . Princeton University . en . October 8, 2024 . https://web.archive.org/web/20241008150359/https://www.princeton.edu/news/2024/10/08/princetons-john-hopfield-receives-nobel-prize-physics . live .
  8. Web site: 1976 . The Life and the Structure of Hemoglobin, American Institute of Physics . October 9, 2024 . Orego State Documentary History of Linus Pauling.
  9. Book: Hey, Anthony . Feynman And Computation . March 8, 2018 . CRC Press . 978-0-429-96900-3 . en.
  10. Hillis . W. Daniel . February 1, 1989 . Richard Feynman and the Connection Machine . Physics Today . 42 . 2 . 78–83 . 10.1063/1.881196 . 1989PhT....42b..78H . 0031-9228.
  11. Web site: Caltech Celebrates 30 Years of its Computation and Neural Systems Option Caltech Alumni . October 8, 2024 . en-US . October 8, 2024 . https://web.archive.org/web/20241008150405/https://alumni.caltech.edu/caltech-celebrates-30-years-of-its-computation-and-neural-systems-option/ . live .
  12. Web site: Gerald Mahan Obituary (1937 - 2021) - New York, NY - The Oregonian . 2024-10-13 . Legacy.com.
  13. Li . Zhaoping . A model of the olfactory bulb and beyond . 1990 . phd . California Institute of Technology . en.
  14. Hopfield . J. J. . December 1, 1958 . Theory of the Contribution of Excitons to the Complex Dielectric Constant of Crystals . Physical Review . en . 112 . 5 . 1555–1567 . 10.1103/PhysRev.112.1555 . 1958PhRv..112.1555H . 0031-899X.
  15. Book: Agranovich, Vladimir M. . Excitations in Organic Solids . February 12, 2009 . OUP Oxford . 978-0-19-155291-5 . en . October 8, 2024 . October 8, 2024 . https://web.archive.org/web/20241008150402/https://books.google.com/books?id=dYePg7KvyIIC&dq=history+of+polariton+hopfield&pg=PA106 . live .
  16. Huttner . B. . Barnett . S. M. . 1992 . Dispersion and Loss in a Hopfield Dielectric . Europhysics Letters . en . 18 . 6 . 487 . 10.1209/0295-5075/18/6/003 . 1992EL.....18..487H . 0295-5075 . October 8, 2024 . October 8, 2024 . https://web.archive.org/web/20241008143515/https://iopscience.iop.org/article/10.1209/0295-5075/18/6/003 . live .
  17. Reynolds . D. C. . Litton . C. W. . Collins . T. C. . 1965 . Some Optical Properties of Group II-VI Semiconductors (I) . Physica Status Solidi B . en . 9 . 3 . 645–684 . 10.1002/pssb.19650090302 . 1965PSSBR...9..645R . 0370-1972.
  18. Book: Zangwill, Andrew . A Mind Over Matter: Philip Anderson and the Physics of the Very Many . January 8, 2021 . Oxford University Press . 978-0-19-264055-0 . en.
  19. Topp . William C. . Hopfield . John J. . 1973-02-15 . Chemically Motivated Pseudopotential for Sodium . Physical Review B . en . 7 . 4 . 1295–1303 . 10.1103/PhysRevB.7.1295 . 1973PhRvB...7.1295T . 0556-2805.
  20. Book: Martin, Richard M. . Electronic Structure: Basic Theory and Practical Methods . 2020-08-27 . Cambridge University Press . 978-1-108-42990-0 . en.
  21. Book: Marx . Dominik . Ab Initio Molecular Dynamics: Basic Theory and Advanced Methods . Hutter . Jürg . 2009-04-30 . Cambridge University Press . 978-1-139-47719-2 . en.
  22. Hopfield . J. J. . 1974 . Kinetic Proofreading: A New Mechanism for Reducing Errors in Biosynthetic Processes Requiring High Specificity . Proceedings of the National Academy of Sciences . en . 71 . 10 . 4135–4139 . 10.1073/pnas.71.10.4135 . free . 0027-8424 . 434344 . 4530290. 1974PNAS...71.4135H .
  23. Book: Flyvbjerg . Henrik . Physics of Bio-Molecules and Cells: Les Houches Session LXXV, 2–27 July 2001 . Jülicher . Frank . Ormos . Pal . David . Francois . July 1, 2003 . Springer Science & Business Media . 978-3-540-45701-5 . en . October 8, 2024 . October 8, 2024 . https://web.archive.org/web/20241008150403/https://books.google.com/books?id=QSVKAAAAQBAJ&dq=biography+hopfield+kinetic+proofreading&pg=PA449 . live .
  24. Hopfield . J J . April 1982 . Neural networks and physical systems with emergent collective computational abilities. . Proceedings of the National Academy of Sciences of the United States of America . 79 . 8 . 2554–2558 . 10.1073/pnas.79.8.2554 . free . 0027-8424 . 6953413. 346238 . 1982PNAS...79.2554H .
  25. Hopfield . J J . 1984 . Neurons with graded response have collective computational properties like those of two-state neurons. . Proceedings of the National Academy of Sciences of the United States of America . 81 . 10 . 3088–3092 . 0027-8424 . 6587342 . 10.1073/pnas.81.10.3088 . free. 345226 . 1984PNAS...81.3088H .
  26. Hopfield . John J. . March 1, 2014 . Whatever Happened to Solid State Physics? . Annual Review of Condensed Matter Physics . en . 5 . 1 . 1–13 . 10.1146/annurev-conmatphys-031113-133924 . 2014ARCMP...5....1H . 1947-5454. free .
  27. Hopfield . J. J. . Tank . D. W. . July 1, 1985 . "Neural" computation of decisions in optimization problems . Biological Cybernetics . en . 52 . 3 . 141–152 . 10.1007/BF00339943 . 4027280 . 1432-0770 . October 8, 2024 . October 8, 2024 . https://web.archive.org/web/20241008150833/https://link.springer.com/article/10.1007/BF00339943 . live .
  28. Hopfield . John J. . Tank . David W. . August 8, 1986 . Computing with Neural Circuits: A Model . Science . en . 233 . 4764 . 625–633 . 10.1126/science.3755256 . 3755256 . 1986Sci...233..625H . 0036-8075 . October 8, 2024 . April 14, 2024 . https://web.archive.org/web/20240414215541/https://www.science.org/doi/10.1126/science.3755256 . live .
  29. The Nobel Committee for Physics . October 8, 2024 . Scientifc Background to the Nobel Prize in Physics 2024 . The Royal Swedish Academy of Sciences . October 8, 2024 . October 8, 2024 . https://web.archive.org/web/20241008115608/https://www.nobelprize.org/uploads/2024/09/advanced-physicsprize2024.pdf . live .
  30. Book: Pruessner, Gunnar . Self-Organised Criticality: Theory, Models and Characterisation . 2012-08-30 . Cambridge University Press . 978-0-521-85335-4 . en.
  31. Hopfield . John J. . 1994-02-01 . Neurons, Dynamics and Computation . Physics Today . 47 . 2 . 40–46 . 10.1063/1.881412 . 1994PhT....47b..40H . 0031-9228.
  32. Hopfield . J J . Herz . A V . 1995-07-18 . Rapid local synchronization of action potentials: toward computation with coupled integrate-and-fire neurons. . Proceedings of the National Academy of Sciences . en . 92 . 15 . 6655–6662 . 10.1073/pnas.92.15.6655 . 0027-8424 . 41391 . 7624307 . free. 1995PNAS...92.6655H .
  33. Beggs . John . 2007 . Neuronal avalanche . Scholarpedia . en . 2 . 1 . 1344 . 10.4249/scholarpedia.1344 . free . 2007SchpJ...2.1344B . 1941-6016.
  34. Krotov . Dmitry . Hopfield . John J. . 2016 . Dense Associative Memory for Pattern Recognition . live . Advances in Neural Information Processing Systems . Curran Associates, Inc. . 29 . 1606.01164 . https://web.archive.org/web/20240619113658/https://papers.nips.cc/paper_files/paper/2016/hash/eaae339c4d89fc102edd9dbdb6a28915-Abstract.html . June 19, 2024 . October 8, 2024.
  35. Book: Kahana . Michael J. . The Oxford Handbook of Human Memory, Two Volume Pack: Foundations and Applications . Wagner . Anthony D. . 2024 . Oxford University Press . 978-0-19-774614-1 . en.
  36. Web site: Feathers . Todd . 2024-10-08 . Nobel Prize Goes to 'Godfathers of AI' Who Now Fear Their Work Is Growing Too Powerful . 2024-10-09 . Gizmodo . en-US.
  37. Web site: Pause Giant AI Experiments: An Open Letter . 2024-10-09 . Future of Life Institute . en-US.
  38. Web site: 2024-10-09 . Nobel winner John Hopfield warns of 'catastrophe' if AI advances are not 'controlled' . Hindustan Times.
  39. Web site: Fellows Database Alfred P. Sloan Foundation . 2024-10-10 . sloan.org . en.
  40. Web site: John J. Hopfield – John Simon Guggenheim Memorial Foundation… . 2024-10-10 . en-US.
  41. Web site: APS Fellowship recipients . American Physical Society.
  42. Web site: APS Press Office . 8 October 2024 . American Physical Society congratulates winners of the 2024 Nobel Prize in Physics .
  43. Web site: John J. Hopfield . live . https://web.archive.org/web/20190324140236/http://www.nasonline.org/member-directory/members/54422.html . March 24, 2019 . May 24, 2020 . www.nasonline.org.
  44. Web site: October 12, 2023 . John Joseph Hopfield . live . https://web.archive.org/web/20241008161356/https://www.amacad.org/person/john-joseph-hopfield . October 8, 2024 . May 24, 2020 . American Academy of Arts & Sciences.
  45. Web site: APS Member History . live . https://web.archive.org/web/20231018060406/https://search.amphilsoc.org/memhist/search?creator=John+Hopfield+&title=&subject=&subdiv=&mem=&year=&year-max=&dead=&keyword=&smode=advanced . October 18, 2023 . May 24, 2020 . search.amphilsoc.org.
  46. Web site: John Hopfield, Array of Contemporary Physicists . October 19, 2013 . https://web.archive.org/web/20131019172143/http://www.aip.org/history/acap/biographies/bio.jsp?hopfieldj . October 19, 2013 . dead .
  47. Web site: Honors and Award Winners . October 8, 2024 . American Physical Society.
  48. October 5, 1983 . Biologist awarded $224,000 - tax free, no strings attached . CalTech News . 17 . 5 . 6.
  49. Web site: Golden Plate Awardees of the American Academy of Achievement . live . https://web.archive.org/web/20161215023909/https://achievement.org/our-history/golden-plate-awards/#science-exploration . December 15, 2016 . June 26, 2020 . American Academy of Achievement .
  50. Spring 1988 . Random Walk - Honors and Awards . Engineering and Science . Record Number: CaltechES:51.3.0 . CalTech . 51 . 3 . 43.
  51. Web site: Past Recipients - IEEE Computational Intelligence Society . 2024-10-10 . cis.ieee.org . en-gb.
  52. Web site: Dirac Medallist 2001 ICTP . October 20, 2023 . www.ictp.it . October 8, 2024 . https://web.archive.org/web/20241008150847/https://www.ictp.it/home/dirac-medallist-2001 . live .
  53. October 1, 2001 . Princeton Physicist Garners Dirac Medal . Physics Today . en . 54 . 10 . 85 . 10.1063/1.1420565 . 0031-9228 . free . 2001PhT....54S..85. . October 8, 2024 . October 8, 2024 . https://web.archive.org/web/20241008170347/https://pubs.aip.org/physicstoday/article/54/10/85/935313/Princeton-Physicist-Garners-Dirac-Medal . live .
  54. Web site: Pender Lecture . 2024-10-13 . en-US.
  55. Web site: Albert Einstein World Award of Science 2005. August 13, 2013. dead. https://web.archive.org/web/20131023001446/http://www.consejoculturalmundial.org/winners-science-johnj.php. October 23, 2013.
  56. Web site: Fritz London Memorial Lecture Department of Physics . 2024-10-13 . physics.duke.edu . en.
  57. Web site: MacPherson . Kitta . 8 May 2009 . Hopfield wins IEEE's Rosenblatt Award . 2024-10-10 . Princeton University . en.
  58. Web site: Swartz Prize awarded to John Hopfield for contributions to computational neuroscience . 2024-10-10 . Office of the Dean for Research . en.
  59. Web site: December 10, 2018 . John J. Hopfield Named Winner of 2019 Benjamin Franklin Medal in Physics - IAS News Institute for Advanced Study . October 9, 2024 . www.ias.edu . en.
  60. Web site: STATPHYS28 . October 8, 2024 . statphys28.org . April 14, 2024 . https://web.archive.org/web/20240414210119/https://statphys28.org/boltzmannmedal.html . live .
  61. Web site: The Nobel Prize in Physics 2024 . October 8, 2024 . Nobel Media AB . October 8, 2024 . https://web.archive.org/web/20241008150842/https://www.nobelprize.org/prizes/physics/2024/summary/ . live .
  62. Announcement of the 2024 Nobel Prize in Physics . October 8, 2024 . Nobel Prize . October 8, 2024 . YouTube . October 8, 2024 . https://web.archive.org/web/20241008125632/https://www.youtube.com/watch?v=SBGG4WNweEc . live .

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "John Hopfield".

Except where otherwise indicated, Everything.Explained.Today is © Copyright 2009-2025, A B Cryer, All Rights Reserved. Cookie policy.