John Bardeen (May 23, 1908 – January 30, 1991) was an American physicist and electrical engineer, the only person to have won the Nobel Prize in Physics twice: first in 1956 with William Shockley and Walter Brattain for the invention of the transistor; and again in 1972 with Leon Neil Cooper and John Robert Schrieffer for a fundamental theory of conventional superconductivity known as the BCS theory.

The transistor revolutionized the electronics industry, allowing the Information Age to occur, and made possible the development of almost every modern electronical device, from telephones to computers to missiles. Bardeen's developments in superconductivity, which won him his second Nobel, are used in magnetic resonance imaging (MRI). In 1990, John Bardeen appeared on LIFE Magazine's list of "100 Most Influential Americans of the Century."

John Bardeen was born in Madison, Wisconsin, on May 23, 1908. He was the second son of Dr. Charles Russell Bardeen and Althea Harmer Bardeen. He was one of five children. His father, Charles Bardeen, was Professor of Anatomy and the first Dean of the Medical School of the University of Wisconsin – Madison. Althea Bardeen, before marrying, had taught at the Dewey Laboratory School and run an interior decorating business; after marriage she was an active figure in the art world.

Bardeen's talent for mathematics was recognized early. His seventh grade mathematics teacher encouraged Bardeen in pursuing advanced work, and years later, Bardeen credited him for "first exciting [his] interest in mathematics."

Althea Bardeen became seriously ill with cancer when John was 12 years old. Charles Bardeen downplayed the seriousness of her illness so that it would not affect his children. John was stunned when his mother died.

Bardeen attended the University High School at Madison for several years, but graduated from Madison Central High School in 1923. He graduated from high school at age fifteen, even though he could have graduated several years earlier. His graduation was postponed due to taking additional courses at another high school and also partly because of his mother's death. He entered the University of Wisconsin – Madison in 1923. While in college he joined the Zeta Psi fraternity. He raised the needed membership fees partly by playing billiards. He was initiated as a member of Tau Beta Pi engineering honor society. He chose engineering because he didn't want to be an academic like his father and also because it is mathematical. He also felt that engineering had good job prospects.

Bardeen received his B.S. in electrical engineering in 1928 from the University of Wisconsin – Madison. He graduated in 1928 despite also having taken a year off during his degree to work in Chicago. He had taken all the graduate courses in physics and mathematics that had interested him, and, in fact, graduated in five years, one more than usual; this allowed him time to also complete a Master's thesis, supervised by Leo J. Peters. He received his M.S. in electrical engineering in 1929 from Wisconsin. His mentors in mathematics were Warren Weaver and Edward Van Vleck. His primary physics mentor was John Hasbrouck van Vleck, but he was also much influenced by visiting scholars such as Paul Dirac, Werner Heisenberg and Arnold Sommerfeld.

Bardeen was unsuccessful in his 1929 application to Trinity College, Cambridge, for one of their coveted fellowships.

Bardeen stayed on for some time at Wisconsin furthering his studies, but he eventually went to work for Gulf Research Laboratories, the research arm of the Gulf Oil Company, based in Pittsburgh. From 1930 to 1933, Bardeen worked there on the development of methods for the interpretation of magnetic and gravitational surveys. He worked as a geophysicist. After the work failed to keep his interest, he applied and was accepted to the graduate program in mathematics at Princeton University.

Bardeen studied both mathematics and physics as a graduate student, ending up writing his thesis on a problem in solid state physics, under Nobel laureate physicist Eugene Wigner. Before completing his thesis, he was offered a position as Junior Fellow of the Society of Fellows at Harvard University in 1935. He spent the next three years there, from 1935 to 1938, working with Nobel laureate physicist John Hasbrouck van Vleck and to-be laureate Percy Williams Bridgman on problems in cohesion and electrical conduction in metals, and also did some work on level density of nuclei. He received his Ph.D. in mathematical physics from Princeton University in 1936.

In the fall of 1938, Bardeen started in his new role as assistant professor at the University of Minnesota.

In 1941, the world was embroiled in war, and Bardeen was convinced by his colleagues to take a leave of absence and work for the Naval Ordnance Laboratory. He would stay there for four years. In 1943 he was invited to join the Manhattan Project, but he declined, since he did not want to uproot his family. He received the Meritorious Civilian Service Award for his service at the NOL.

After the end of World War II, Bardeen started seeking a return to academia, but the University of Minnesota did not realize the importance of the young field of solid state physics. They offered him only a small raise. Bardeen's expertise in solid state physics made him invaluable to Bell Labs, which was just starting a solid state division. Remembering the lack of support he had received previously from the university to pursue his research, he decided to take a lucrative offer from Bell Labs in 1945.

In October 1945, John Bardeen began work at Bell Labs. Bardeen was a member of a Solid State Physics Group, led by William Shockley and chemist Stanley Morgan. Other personnel working in the group were Walter Brattain, physicist Gerald Pearson, chemist Robert Gibney, electronics expert Hilbert Moore and several technicians. He moved his family to Summit, New Jersey. John Bardeen had met William Shockley when they were both in school in Massachusetts. He rekindled his friendship with Walter Brattain. Bardeen knew Walter Brattain from his graduate school days at Princeton. He had previously met Brattain through Brattain's brother, Bob Brattain. Bob Brattain was also a Princeton graduate student. Over the years the friendship of Bardeen and Brattain grew, both in the lab, where Brattain put together the experiments and Bardeen wove theories to explain the results and also on the golf course where they spent time on the weekends.

The assignment of the group was to seek a solid state alternative to fragile glass vacuum tube amplifiers. Their first attempts were based on Shockley's ideas about using an external electrical field on a semiconductor to affect its conductivity. These experiments mysteriously failed every time in all sorts of configurations and materials. The group was at a standstill until Bardeen suggested a theory that invoked surface states that prevented the field from penetrating the semiconductor. The group changed its focus to study these surface states, and they met almost daily to discuss the work. The rapport of the group was excellent, and ideas were freely exchanged. By the winter of 1946 they had enough results that Bardeen submitted a paper on the surface states to Physical Review. Brattain started experiments to study the surface states through observations made while shining a bright light on the semiconductor's surface. This led to several more papers (one of them co-authored with Shockley), which estimated the density of the surface states to be more than enough to account for their failed experiments. The pace of the work picked up significantly when they started to surround point contacts between the semiconductor and the conducting wires with electrolytes. Moore built a circuit that allowed them to vary the frequency of the input signal easily and suggested that they use glycol borate (gu), a viscous chemical that didn't evaporate. Finally they began to get some evidence of power amplification when Pearson, acting on a suggestion by Shockley, put a voltage on a droplet of gu placed across a P-N junction.

In the spring of 1947, William Shockley set Brattain and Bardeen to a task to explain why an amplifier he had devised didn't work. At the heart of the amplifier was a crystal of silicon. They would switch to germanium after some months. To figure out what was going on, Bardeen had to remember some of the quantum mechanics research that he had done on semiconductors while he was completing his Ph.D. at Princeton University. Bardeen had also come up with some new theories himself. By observing Brattain's experiments, Bardeen realized that everyone had been falsely assuming electrical current traveled through all parts of the germanium in a similar way. The electrons behaved differently at the surface of the metal. If they could control what was happening at the surface, the amplifier should work.

On December 23, 1947, Bardeen and Brattain — working without Shockley — succeeded in creating a point - contact transistor that achieved amplification. By the next month, Bell Labs' patent attorneys started to work on the patent applications.

Bell Labs' attorneys soon discovered that Shockley's field effect principle had been anticipated and patented in 1930 by Julius Lilienfeld, who filed his MESFET - like patent in Canada on October 22, 1925. Although the patent appeared "breakable" (it could not work), the patent attorneys based one of its four patent applications only on the Bardeen - Brattain point contact design. Three others submitted at the same time covered the electrolyte - based transistors with Bardeen, Gibney and Brattain as the inventors. Shockley's name was not on any of these patent applications. This angered Shockley, who thought his name should also be on the patents because the work was based on his field effect idea. He even made efforts to have the patent written only in his name, and told Bardeen and Brattain of his intentions.

At the same time, Shockley secretly continued his own work to build a different sort of transistor based on junctions instead of point contacts; he expected this kind of design would be more likely to be viable commercially. Shockley worked furiously on his magnum opus, Electrons and Holes in Semiconductors, which was finally published as a 558 page treatise in 1950. In it, Shockley worked out the critical ideas of drift and diffusion and the differential equations that govern the flow of electrons in solid state crystals. Shockley's diode equation is also described. This seminal work became the "bible" for an entire generation of scientists working to develop and improve new variants of the transistor and other devices based on semiconductors.

Shockley was dissatisfied with certain parts of the explanation for how the point contact transistor worked and conceived of the possibility of minority carrier injection. This led Shockley to ideas for what he called a "sandwich transistor." This resulted in the junction transistor, which was announced at a press conference on July 4, 1951. Shockley obtained a patent for this invention on September 25, 1951. Different fabrication methods for this device were developed but the "diffused - base" method became the method of choice for many applications. It soon eclipsed the point contact transistor, and it and its offspring became overwhelmingly dominant in the marketplace for many years. Shockley continued as a group head to lead much of the effort at Bell Labs to improve it and its fabrication for two more years.

Shockley took the lion's share of the credit in public for the invention of transistor, which led to a deterioration of Bardeen's relationship with Shockley. Bell Labs management, however, consistently presented all three inventors as a team. Shockley eventually infuriated and alienated Bardeen and Brattain, and he essentially blocked the two from working on the junction transistor. Bardeen began pursuing a theory for superconductivity and left Bell Labs in 1951. Brattain refused to work with Shockley further and was assigned to another group. Neither Bardeen nor Brattain had much to do with the development of the transistor beyond the first year after its invention.

The "transistor" (a combination of "transfer" and "resistor") was 1/50 as large as the vacuum tubes it replaced in televisions and radios and allowed electrical devices to become more compact.

By 1951, Bardeen was looking for a new job. Fred Seitz, a friend of Bardeen, convinced the University of Illinois at Urbana - Champaign to make Bardeen an offer of $10,000 a year. Bardeen accepted the offer and left Bell Labs. He joined the engineering faculty and the physics faculty at the University of Illinois at Urbana - Champaign in 1951. He was Professor of Electrical Engineering and of Physics at Illinois. His first Ph.D. student was Nick Holonyak (1954), the inventor of the first LED in 1962.

At Illinois, he established two major research programs, one in the Electrical Engineering Department and one in the Physics Department. The research program in the Electrical Engineering Department dealt with both experimental and theoretical aspects of semiconductors, and the research program in the Physics Department dealt with theoretical aspects of macroscopic quantum systems, particularly superconductivity and quantum liquids.

He was an active professor at Illinois from 1951 to 1975 and then became Professor Emeritus.

In 1956, John Bardeen shared the Nobel Prize in Physics with William Shockley of Semiconductor Laboratory of Beckman Instruments and Walter Brattain of Bell Telephone Laboratories "for their researches on semiconductors and their discovery of the transistor effect".

Bardeen first heard the news that the Nobel Prize in Physics had been awarded to him, Brattain and Shockley when he was making breakfast and listening to the radio on the morning of Thursday, November 1, 1956.

The Nobel Prize ceremony took place in Stockholm, Sweden, on the evening of Monday, December 10. Bardeen, Brattain and Shockley received their awards that night from King Gustaf VI Adolf and then adjourned for a great banquet in their honor. On that night the three men were together, and they remembered the days when they had been friends and a great research team.

Bardeen brought only one of his three children to the Nobel Prize ceremony. His two sons were studying at Harvard University, and Bardeen did not want to disrupt their studies. King Gustav scolded Bardeen because of this, and Bardeen assured the King that the next time he would bring all his children to the ceremony. He kept his promise.

In 1957, John Bardeen, in collaboration with Leon Cooper and his doctoral student John Robert Schrieffer, proposed the standard theory of superconductivity known as the BCS theory (named for their initials).

BCS theory explains conventional superconductivity, the ability of certain metals at low temperatures to conduct electricity without electrical resistance. BCS theory views superconductivity as a macroscopic quantum mechanical effect. It proposes that electrons with opposite spin can become paired, forming Cooper pairs. Independently and at the same time, the superconductivity phenomenon was explained by Nikolay Bogoliubov by means of the so-called Bogoliubov transformations.

In many superconductors, the attractive interaction between electrons (necessary for pairing) is brought about indirectly by the interaction between the electrons and the vibrating crystal lattice (the phonons). Roughly speaking the picture is the following: An electron moving through a conductor will attract nearby positive charges in the lattice. This deformation of the lattice causes another electron, with opposite "spin", to move into the region of higher positive charge density. The two electrons are then held together with a certain binding energy. If this binding energy is higher than the energy provided by kicks from oscillating atoms in the conductor (which is true at low temperatures), then the electron pair will stick together and resist all kicks, thus not experiencing resistance.

In 1972, John Bardeen shared the Nobel Prize in Physics with Leon Neil Cooper of Brown University and John Robert Schrieffer of the University of Pennsylvania for their jointly developed theory of superconductivity, usually called the BCS - theory.

Bardeen did bring all his children to the Nobel Prize ceremony in Stockholm, Sweden.

This was Bardeen's second Nobel Prize in Physics. He became the first person to win two Nobel Prizes in the same field. He also became the third person out of only four to win two Nobel Prizes. The first two were Marie Curie, who received the Nobel Prize in Physics in 1903 and Nobel Prize in Chemistry in 1911, and Linus Pauling, who received the Nobel Prize in Chemistry in 1954 and Nobel Peace Prize in 1962. In 1980, Frederick Sanger won his second Nobel Prize in Chemistry and became the fourth person to win two Nobel Prizes.

Bardeen gave much of his Nobel Prize money to fund the Fritz London Memorial Lectures at Duke University.

In 1952, he was awarded the Franklin Institute's Stuart Ballantine Medal. In 1959, he was elected a Fellow of the American Academy of Arts and Sciences. In 1965, he was awarded the National Medal of Science. In 1971, Bardeen received the IEEE Medal of Honor for "his profound contributions to the understanding of the conductivity of solids, to the invention of the transistor, and to the microscopic theory of superconductivity." In 1975 he was awarded the Franklin Medal. On January 10, 1977, John Bardeen was presented with the Presidential Medal of Freedom by President Gerald Ford. He was represented at the ceremony by his son, William Bardeen. Bardeen was one of 11 recipients given the Third Century Award from President George H.W. Bush in 1990 for "exceptional contributions to American society" and was granted a gold medal from the Soviet Academy of Sciences in 1988.

Bardeen was also an important advisor to Xerox Corporation. Though quiet by nature, he took the uncharacteristic step of urging Xerox executives to keep their California research center, Xerox PARC, afloat when the parent company was suspicious that its research center would amount to little.

Bardeen died of heart disease at Brigham and Women's Hospital in Boston, Massachusetts, on January 30, 1991. Although he lived in Champaign - Urbana, he had come to Boston for medical consultation. Bardeen and his wife Jane (1907 – 1997) are buried in Forest Hill Cemetery, Madison, WI. They were survived by three children, James & William and Elizabeth Bardeen Greytak, and six grandchildren.

Bardeen married Jane Maxwell on July 18, 1938. While at Princeton, he met Jane during a visit to his old friends in Pittsburgh.

Bardeen was a man with a very unassuming personality. While he served as a professor for almost 40 years at the University of Illinois, he was best remembered by neighbors for hosting cookouts where he would cook for his friends, many of whom were unaware of his accomplishments at the university. He enjoyed playing golf and going on picnics with his family.

It has been said that Bardeen proves wrong the stereotype of the "crazy scientist." Lillian Hoddeson, a University of Illinois historian who wrote a book on Bardeen, said that because he "differed radically from the popular stereotype of genius and was uninterested in appearing other than ordinary, the public and the media often overlooked him."

In honor of Professor Bardeen, the engineering quadrangle at the University of Illinois at Urbana - Champaign is named the Bardeen.

Also in honor of Bardeen, Sony Corporation endowed a $53 million John Bardeen professorial chair at the University of Illinois at Urbana - Champaign, beginning in 1990. The current John Bardeen Professor is Nick Holonyak, Bardeen's first doctoral student and protege.

At the time of Bardeen's death, then University of Illinois chancellor Morton Weir said, "It is a rare person whose work changes the life of every American; John's did."

Bardeen was honored on a March 6, 2008, United States postage stamp as part of the "American Scientists" series. The $0.41 stamp was unveiled in a ceremony at the University of Illinois. His citation reads: "Theoretical physicist John Bardeen (1908 – 1991) shared the Nobel Prize in Physics twice -- in 1956, as co-inventor of the transistor and in 1972, for the explanation of superconductivity. The transistor paved the way for all modern electronics, from computers to microchips. Diverse applications of superconductivity include infrared sensors and medical imaging systems." The other scientists on the "American Scientists" sheet include Gerty Cori, biochemist; Linus Pauling, chemist; and Edwin Hubble, astronomer.