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Portrait of Leon N. Cooper
Photo: Kenneth C. Zirkel, Own work · CC BY-SA 3.0 via Wikimedia Commons

Nobel Prize in Physics · 1972

Leon N. Cooper

He showed how electrons pair up, the key to current flowing with zero resistance, then turned to how the brain learns.

The Nobel citation: “for their jointly developed theory of superconductivity, usually called the BCS-theory”
Born
February 28, 1930, New York, NY, USA
Died
October 23, 2024, Providence, RI, USA
Shared with
John Bardeen, Robert Schrieffer
Affiliation at the time
Brown University, USA

Physics prize

1972

Shared with 2 other laureates.

Age that year

42years

Born in 1930.

Sources cited

20

Fact-checked September 24, 2026.

  • He was 26 when he published the idea of the Cooper pair in 1956; the Nobel Foundation notes the prize-winning theory was done while he was still in his 20s.
  • Bohr, Heisenberg and Feynman had all tried to explain superconductivity. Feynman warned that anyone who tackled it would find they were not clever enough.
  • A missing piece of the theory came to him during a concert at the University of Illinois. Whether it worked hinged on a single plus or minus sign.
  • The Big Bang Theory's Sheldon Cooper has often been reported to be named partly after him.
  • After the Nobel Prize he turned to the brain: his 1982 BCM theory described how connections between neurons strengthen and weaken as we learn.

The breakthrough

Cooper pairs and the BCS theory of superconductivity (1956-1957)

Cool certain metals to a few degrees above absolute zero and their electrical resistance vanishes. In one test, a current kept circling a cold lead ring for two and a half years with no measurable loss. The Dutch physicist Kamerlingh Onnes discovered this superconductivity in 1911, but for more than 40 years nobody could explain it. Electrons all carry negative charge and repel each other, so how could they move in perfect order? In 1956 Cooper, then 26 and working with John Bardeen at the University of Illinois, found a key piece. He showed that inside a cold metal, even a weak attraction lets two electrons bind into a pair. The attraction comes from the metal itself: a passing electron slightly disturbs the lattice of atoms around it, and that disturbance draws in a second electron. These are now called Cooper pairs. In 1957 Bardeen, Cooper and Bardeen's graduate student Robert Schrieffer showed how vast numbers of pairs lock together into one coordinated state. Picture a huge crowd of dancers moving in step: no single dancer can stumble without disturbing everyone, so small bumps cannot knock the crowd off course. Breaking a pair costs a minimum amount of energy, so the jostling that causes resistance in ordinary metals cannot slow the current. One crucial term in the calculation came to Cooper during a concert; its sign decided whether the whole effect survived. The BCS theory, named for their initials, explained conventional low-temperature superconductors in detail and predicted new effects.[3],[4],[5],[6],[7],[9],[11],[17],[19],[20]

“A theory (though it may guide us in reaching them) does not produce the treasures the world holds.”
Leon N. Cooper, From his Nobel lecture of 11 December 1972, answering the question he and his colleagues were often asked about the practical uses of their theory.[5]

What it meant for humanity

BCS theory produced no single invention, and Cooper himself cautioned that theory should not take credit for many practical uses of superconductivity. Its gifts were understanding and prediction. By explaining why some metals lose all resistance, it gave physicists and engineers a working map of the phenomenon, and the Nobel committee noted that it predicted new effects and opened new fields of research. The most important, in Cooper's own view, was the Josephson effect, found a few years later: SQUIDs, sensors built on it, measure magnetic fields with extreme sensitivity. Josephson junctions, two superconductors separated by a thin insulating barrier, are also used to measure fundamental physical constants precisely. They were at the heart of the experiments honored by the 2025 Nobel Prize in Physics, and superconducting circuits built from them are one of the approaches being explored for quantum computers. Superconductivity itself creates the strong magnetic fields in MRI body scanners and the magnets of particle accelerators. The pairing idea also traveled: physicists applied it to atomic nuclei, neutron stars and liquid helium-3, and Steven Weinberg wrote that particle physicists learned the idea of spontaneous symmetry breaking from BCS, a thread that led to the electroweak theory and the Higgs boson. Cooper's second career touched another science. His 1982 BCM theory was one of the first mathematical models showing how changes at synapses could produce learning and memory, and its central prediction, a threshold that shifts with a neuron's recent activity, was later supported by experiments on the visual cortex. The brain-science center he founded at Brown in 1973 helped lay the groundwork for the university's Carney Institute for Brain Science.

  • Cooper said the most important application of the theory by far was the SQUID, a magnetic-field sensor based on the Josephson effect, which he called a consequence of the BCS theory that he had not foreseen.[6]
  • The 2025 Nobel Prize in Physics honored experiments on a chip in which billions of Cooper pairs behaved as one quantum object; such superconducting circuits are one route being explored toward quantum computers.[12]
  • Steven Weinberg wrote that particle physicists learned the idea of spontaneous symmetry breaking from BCS theory, a line of thought that led to the electroweak theory and the prediction of the Higgs boson.[11]
  • The 1982 BCM theory predicted that a neuron's threshold for strengthening or weakening a connection slides with its recent activity; a review Cooper co-wrote cites 1996 experiments in rat visual cortex that supported it.[13],[14]
  • The Center for Neural Science that he founded and first directed at Brown in 1973 helped build an early foundation for the university's Carney Institute for Brain Science.[1],[9]

Impact in numbers

We record no numbers for Cooper. BCS theory explained superconductivity; it did not invent the wires, magnets and sensors that use it, and in his Nobel lecture Cooper said theory should not take credit for many practical uses of the phenomenon. Any count of MRI scans or dollars credited to him would be guesswork. What can be said plainly is where his work lives on. BCS theory is widely accepted as the explanation of conventional superconductivity, though it applies only to low-temperature superconductors. The Josephson effect, SQUID sensors and today's superconducting quantum circuits grew out of the physics it described, and it lent particle physics the idea of spontaneous symmetry breaking that runs through the theory of the Higgs boson. In neuroscience, his BCM theory gave researchers a testable model of how experience reshapes the visual cortex, and by the early 1990s his company Nestor was selling neural-network products such as handwriting-recognition software. We record no harm figure: we found no documented harm from his theory, and no record of specific harm from Nestor's military applications.

Fundamental scienceTechnology

No number is given here on purpose. Some contributions cannot be counted honestly, and we would rather describe them than invent a figure.

The double edge

We found no documented harm from the BCS theory itself. One strand of Cooper's applied work was dual-use. The Nobel Foundation's biography describes Nestor, the neural-network company he co-founded and co-chaired, as applying its pattern-recognition systems to both commercial and military uses, including classifying targets in sonar, radar and imaging systems, and it lists him as a member of the Defense Science Board. We found no record of specific harm caused by these systems.

  • Minor

    Neural networks for military target recognition

    According to his Nobel Foundation biography, Nestor, which Cooper co-founded and co-chaired, sold adaptive pattern-recognition systems for commercial and military uses, such as classifying targets in sonar, radar and imaging data. He also served on the Defense Science Board. We found no record of specific harm from these systems.[1]

Against the odds

Cooper grew up in New York, far from the violence his parents' homelands had known. Both were Jewish immigrants, from Belarus and Poland. From 1918 to 1920, amid the civil war after the Russian Revolution, armed forces on several sides, Red Army troops among them, attacked Jewish communities in western Belarus and Galicia, and tens of thousands of Jews were killed. Cooper's own hardships were those of a family: after his mother died, he and his sister spent part of their childhood in care. He went to the Bronx High School of Science and in 1947 entered Columbia University. A generation earlier, in 1920-22, Columbia had used regional quotas to cut the Jewish share of its students from 40 to 22 percent. By the time Cooper arrived, after World War II, such barriers at private colleges were being lowered, and we found no record that he personally met antisemitic discrimination. Ten years after leaving high school he had helped solve a problem that Niels Bohr, Werner Heisenberg and Richard Feynman had tried and failed to crack. His story is less one of persecution than of a family's loss, and of American higher education opening to the children of Jewish immigrants after the war.

  • —

    Other

    After his mother died, he and his sister spent part of their childhood in care. His father later changed the family surname from Kupchik to Cooper.[7],[8]

  • 1918

    Persecution

    His parents came from Belarus and Poland. Between 1918 and 1920, during the civil war that followed the Russian Revolution, attacks on Jewish communities in western Belarus and Galicia left tens of thousands of Jews dead. We do not know whether his own family was directly affected.[7],[15]

  • 1947

    Quota

    He entered Columbia in 1947. In 1920-22 the college had used regional quotas to cut its Jewish share of students from 40 to 22 percent; such barriers were being lowered after World War II, and we found no record that they affected him.[7],[10],[16]

Jewish background

Both parents JewishRelationship to Jewish identity not documented

Cooper was born in the Bronx as Leon Kupchik, the son of Jewish immigrants from Eastern Europe; Nature's obituary names Belarus and Poland as the family's origins. His father later changed the family surname from Kupchik to Cooper. After his mother died, he and his sister spent part of their childhood in care. The sources we read say nothing about his adult religious practice, and we found no public statement by him about his Jewish identity.[7],[8]

Key dates

  1. February 28, 1930

    Born Leon Kupchik in the Bronx, New York City, the son of Jewish immigrants from Belarus and Poland.[2],[7],[8],[10]

  2. 1947

    Graduates from the Bronx High School of Science and begins physics studies at Columbia University.[7],[10]

  3. 1954

    Earns his PhD at Columbia (A.B. 1951, A.M. 1953) and becomes a member of the Institute for Advanced Study in Princeton.[1]

  4. 1955

    John Bardeen invites him to the University of Illinois to work on superconductivity, a problem he had not heard of before.[1],[7],[10]

  5. November 15, 1956

    Publishes 'Bound Electron Pairs in a Degenerate Fermi Gas', showing that electrons in a metal can form bound pairs, now called Cooper pairs.[7],[19]

  6. December 1, 1957

    Bardeen, Cooper and Schrieffer publish their full 'Theory of Superconductivity' in Physical Review, now known as the BCS theory.[9],[10],[11]

  7. 1958

    Joins Brown University in Providence, Rhode Island, where he stays for the rest of his career.[1],[9]

  8. 1968

    Receives the National Academy of Sciences' Comstock Prize, shared with Robert Schrieffer.[1]

  9. 1972

    Shares the Nobel Prize in Physics with John Bardeen and Robert Schrieffer for the BCS theory of superconductivity.[2],[3]

  10. 1973

    Becomes founding director of Brown's Center for Neural Science, created to study the nervous system and the human brain.[1],[9]

  11. 1975

    Co-founds Nestor, a company that applies artificial neural networks to pattern recognition, with Brown colleague Charles Elbaum.[1],[17],[18]

  12. 1982

    With graduate students Elie Bienenstock and Paul Munro, publishes the BCM theory of how synapses strengthen and weaken as the brain learns.[9],[13]

  13. 2013

    Receives the Susan Culver Rosenberger Medal, the highest honor Brown's faculty can give; he retires from teaching the next year.[9]

  14. October 23, 2024

    Dies in Providence, Rhode Island, aged 94.[2],[9]

Sources

  1. 1.Leon N. Cooper - Biographical · NobelPrize.org (from Nobel Lectures, Physics 1971-1980, World Scientific, 1992)
  2. 2.Leon N. Cooper - Facts · NobelPrize.org (Nobel Prize Outreach)
  3. 3.Press release: The 1972 Nobel Prize in Physics · NobelPrize.org (Royal Swedish Academy of Sciences), 1972
  4. 4.The Nobel Prize in Physics 1972 - Award ceremony speech by Stig Lundqvist · NobelPrize.org, 1972
  5. 5.Microscopic Quantum Interference Effects in the Theory of Superconductivity (Nobel Lecture, 11 December 1972) · NobelPrize.org, 1972
  6. 6.Leon N. Cooper - Interview (Lindau, July 2003) · NobelPrize.org, 2003
  7. 7.Leon Cooper obituary: Nobel laureate who developed theory of superconductivity, by Georgina Ferry (Nature 636, 37) · Nature, 2024
  8. 8.Leon N Cooper (1930-2024): physicist Nobel laureate for superconductivity and molecular neurologist, by Istvan Hargittai (Structural Chemistry 36: 381-383) · Springer Nature, 2024
  9. 9.Passages: Nobel Prize winner and Brown professor of physics Leon Cooper · Brown University, 2024
  10. 10.Leon N. Cooper '51, GSAS'54, Nobel Laureate and Pioneer in Superconductivity · Columbia College Today, Columbia University, 2025
  11. 11.From BCS to the LHC, by Steven Weinberg · CERN Courier, 2008
  12. 12.Quantum properties on a human scale (popular science background, Nobel Prize in Physics 2025) · NobelPrize.org (Royal Swedish Academy of Sciences), 2025
  13. 13.Theory for the development of neuron selectivity: orientation specificity and binocular interaction in visual cortex (Bienenstock, Cooper and Munro, Journal of Neuroscience 2: 32-48) · Society for Neuroscience (via PubMed Central), 1982
  14. 14.BCM theory, by Brian S. Blais and Leon N. Cooper (Scholarpedia 3(3): 1570) · Scholarpedia, 2008
  15. 15.Pogroms (Holocaust Encyclopedia) · United States Holocaust Memorial Museum
  16. 16.How Jewish Quotas Began, by Stephen Steinberg · Commentary, 1971
  17. 17.Leon Cooper · Wikipedia
  18. 18.Nestor's neural chip destiny now in its own hands · Tech Monitor, 1994
  19. 19.Bound Electron Pairs in a Degenerate Fermi Gas, by L. N. Cooper (Physical Review 104: 1189-1190) · American Physical Society, 1956
  20. 20.Leon Cooper (Pioneers in Electricity and Magnetism) · National High Magnetic Field Laboratory, Magnet Academy

Fact-checked on September 24, 2026 by a separate AI fact-checking pass that re-opened the sources, with 3 corrections made. How we check

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