John Bardeen (May 23, 1908 – January 30, 1991) was an American physicist and electrical engineer. He is the only person to have won the Nobel Prize in Physics twice: first in 1956 for the invention of the transistor (shared with William Shockley and Walter Brattain) and again in 1972 for the BCS theory of superconductivity (shared with Leon Cooper and John Robert Schrieffer). Bardeen's work laid the foundation for modern electronics and revolutionized condensed matter physics.
1 Early life and education
1.1 Childhood and family background
John Bardeen was born in Madison, Wisconsin, to Charles Russell Bardeen, a professor of anatomy and dean of the University of Wisconsin Medical School, and Althea Harmer Bardeen. He was the second of five children. His father's academic environment exposed Bardeen to scientific inquiry from an early age. He showed exceptional mathematical ability, skipping several grades in school. After his mother's death in 1920, the family faced personal struggles, but Bardeen’s intellectual drive remained strong.
1.2 Undergraduate studies at the University of Wisconsin–Madison
Bardeen entered the University of Wisconsin–Madison in 1923 at age 15. He initially studied electrical engineering, graduating with a Bachelor of Science in electrical engineering in 1928. He then earned a Master of Science in electrical engineering in 1929 under the supervision of Leo J. Peters, working on antenna radiation and geophysical prospecting. His master's thesis dealt with the mathematical problem of radio wave propagation.
1.3 Graduate work at Princeton University
After working for several years as a geophysicist at Gulf Research Laboratories, Bardeen pursued doctoral studies at Princeton University under the physicist Eugene Wigner. He received his Ph.D. in mathematical physics in 1936. His dissertation, "A Theory of the Work Function of Metals," applied quantum mechanics to the behavior of electrons at metal surfaces—an early contribution to solid-state physics.
2 Career and research
2.1 Bell Telephone Laboratories (1945–1951)
After teaching at the University of Minnesota and serving as a physicist at the Naval Ordnance Laboratory during World War II, Bardeen joined Bell Telephone Laboratories in 1945. He became part of a solid-state physics group led by William Shockley.
2.1.1 Invention of the point-contact transistor
Working with Walter Brattain, Bardeen conducted experiments on semiconductor surfaces. In December 1947, they succeeded in creating the first point-contact transistor, a device capable of amplifying electrical signals. The invention relied on the manipulation of charge carriers in germanium crystals. Bardeen's theoretical understanding of surface states was critical to the design.
2.1.2 Collaboration with Shockley and Brattain
The collaboration between Bardeen, Shockley, and Brattain was productive but strained. Shockley, who had not been directly involved in the point-contact experiments, developed the junction transistor shortly thereafter and insisted on recognition. Despite tensions, the trio shared the 1956 Nobel Prize in Physics. Bardeen later left Bell Labs partly due to conflicts with Shockley.
2.2 University of Illinois at Urbana–Champaign
In 1951, Bardeen joined the faculty at the University of Illinois at Urbana–Champaign as a professor of electrical engineering and physics. He remained there for the rest of his career.
2.2.1 Founding of the solid-state physics group
At Illinois, Bardeen established a leading solid-state physics research group. He recruited talented theorists and experimentalists, fostering a collaborative environment. His group became a hub for condensed matter research, influencing generations of scientists.
2.2.2 BCS theory of superconductivity
2.2.2.1 Formulation of the theory (1957)
Working with Leon Cooper and John Robert Schrieffer, Bardeen developed the microscopic theory of superconductivity, known as BCS theory. The theory explained how electrons in a superconductor form pairs (Cooper pairs) due to lattice vibrations, allowing them to flow without resistance below a critical temperature. The trio published their landmark paper in 1957.
2.2.2.2 Experimental confirmation and Nobel Prize (1972)
BCS theory was quickly confirmed by experiments, such as those measuring the energy gap in superconductors. For this breakthrough, Bardeen, Cooper, and Schrieffer received the 1972 Nobel Prize in Physics. Bardeen thus became the first—and to date only—person to win two Nobel Prizes in physics.
3 Major contributions to physics
3.1 Semiconductor physics and transistor effect
Bardeen's work on semiconductor surfaces and the transistor effect is foundational to modern electronics. His theoretical model of surface states explained why earlier attempts to build field-effect transistors had failed, enabling the point-contact transistor's invention. The subsequent development of integrated circuits and microprocessors traces directly to these discoveries.
3.2 Superconductivity and Cooper pairing
BCS theory, with its concept of Cooper pairing, transformed the understanding of superconductivity. It provided a complete quantum-mechanical explanation, resolved decades of puzzles, and predicted phenomena such as the isotope effect and the Josephson effect. The theory remains central to condensed matter physics.
3.3 Other theoretical work (e.g., surface states, quantum liquids)
Beyond the transistor and superconductivity, Bardeen contributed to theoretical solid-state physics in areas such as surface states, quantum liquids (e.g., He-3 superfluidity), and conductivity in semiconductors. He also worked on problems in quantum electrodynamics and statistical mechanics, though these are less well known outside specialized circles.
4 Awards and honors
4.1 Nobel Prizes (1956, 1972)
Bardeen received the Nobel Prize in Physics in 1956 "for their researches on semiconductors and their discovery of the transistor effect" and in 1972 "for their jointly developed theory of superconductivity, usually called the BCS-theory." He is the only double laureate in physics.
4.2 National Medal of Science (1965)
In 1965, Bardeen was awarded the National Medal of Science by President Lyndon B. Johnson for "his profound contributions to the physics of solids, and especially for his development of the theory of superconductivity."
4.3 Other accolades and memberships
Bardeen received numerous other honors, including the Fritz London Memorial Prize (1962), the IEEE Medal of Honor (1971), and the Lomonosov Gold Medal (1987). He was elected to the National Academy of Sciences, the American Academy of Arts and Sciences, and foreign academies including the Royal Society.
5 Personal life and legacy
5.1 Family and character
Bardeen married Jane Maxwell in 1938; they had three children: James, William, and Elizabeth. He was known for his quiet, modest personality and his intense focus on research. Colleagues described him as unassuming yet exceptionally competitive in his scientific pursuits. He enjoyed golf and was a devoted family man.
5.2 Influence on later generations of physicists
Bardeen's influence extends through his students and collaborators. Many of his Ph.D. students became leading physicists, and his research group at Illinois set a model for large-scale team-based theoretical physics. His dual contributions—the transistor and BCS theory—underpin the Information Age and modern condensed matter physics.
5.3 Depictions in popular culture and memorials
Bardeen is less frequently depicted in popular culture than some peers, but he appears in historical documentaries on the transistor. The John Bardeen Endowed Chair in Physics and Electrical Engineering exists at the University of Illinois. A hall in the Thomas M. Siebel Center for Computer Science is named for him. His alma mater, the University of Wisconsin–Madison, also has a Bardeen Hall.
6 Selected publications
6.1 Key papers on transistors
- J. Bardeen and W. H. Brattain, "The Transistor, A Semi-Conductor Triode," *Physical Review* 74, 230 (1948).
- J. Bardeen, "Surface States and Rectification at a Metal Semi-Conductor Contact," *Physical Review* 71, 717 (1947).
6.2 BCS theory papers
- J. Bardeen, L. N. Cooper, and J. R. Schrieffer, "Microscopic Theory of Superconductivity," *Physical Review* 106, 162 (1957).
- J. Bardeen, L. N. Cooper, and J. R. Schrieffer, "Theory of Superconductivity," *Physical Review* 108, 1175 (1957).