Other meanings of Brian Josephson
Physics
Brian David Josephson (born 9 January 1940) is a Welsh physicist who was awarded the Nobel Prize in Physics in 1973 for his theoretical prediction of the Josephson effect, a phenomenon in which a supercurrent flows between two superconductors separated by a thin insulating barrier. His work has had profound implications for quantum physics and metrology, leading to the development of superconducting quantum interference devices (SQUIDs) and the definition of the volt.
Brian Josephson was born in Cardiff, Wales, to parents of Lithuanian-Jewish descent. His father, Abraham, was a press photographer, and his mother, Mimi, was a secretary. He showed early aptitude for science and mathematics, attending Cardiff High School. In 1957, he entered Trinity College, Cambridge, where he studied mathematics and physics. He graduated in 1960 and began his doctoral research under the supervision of Brian Pippard at the Cavendish Laboratory. His PhD thesis, completed in 1964, was titled 'Non-linear conduction in superconductors', and it was during this period that he made his seminal prediction.1
In 1962, while still a graduate student, Josephson analyzed the behavior of two superconductors separated by a thin insulating barrier. He predicted that a supercurrent could flow through the barrier without any applied voltage, and that the current would oscillate at a frequency proportional to the applied voltage. This became known as the Josephson effect. The prediction was initially met with skepticism, but was quickly confirmed experimentally by Philip Anderson and John Rowell at Bell Labs in 1963.2 The effect is now fundamental to quantum metrology, defining the international standard for the volt via the Josephson constant.
Josephson shared the 1973 Nobel Prize in Physics with Leo Esaki and Ivar Giaever, who were recognized for their work on tunneling in semiconductors and superconductors, respectively. Josephson's contribution was specifically for his theoretical prediction of the supercurrent through a tunnel barrier. After his PhD, he remained at Cambridge, becoming a Fellow of Trinity College and later a Professor of Physics. He continued to work on condensed matter physics but also developed interests in consciousness and parapsychology, which led to controversy within the scientific community.3
The Josephson effect has enabled the development of SQUIDs (Superconducting Quantum Interference Devices), which are the most sensitive magnetometers known, used in medicine for magnetoencephalography and in geophysics for mineral exploration. It also underpins the Josephson voltage standard, which has been used since 1990 to define the volt. More recently, Josephson junctions are being explored for quantum computing applications as qubits.
Beyond his mainstream work, Josephson has pursued unconventional research. In the 1970s, he became interested in the 'mind-matter' interaction and founded the Mind-Matter Unification Project at Cambridge, which investigates the possible role of quantum mechanics in consciousness and psychic phenomena. He has also been a vocal critic of mainstream scientific rejection of such ideas. Additionally, Josephson has contributed to the understanding of the ac Josephson effect, which is used in frequency standards. A lesser-known fact is that his original paper was rejected by the journal 'Physical Review Letters' before being accepted by 'Physics Letters' after a recommendation by John Bardeen.4
This article is about the physicist Brian Josephson. For other uses, see Brian Josephson (disambiguation).
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