Paul Dirac (1902–1984)

Paul Dirac was an English theoretical physicist who laid the foundations of quantum mechanics. He was born in Bristol, but was initially registered as a Swiss national by his father Charles, who insisted the family speak French at home. The young Dirac’s strict upbringing, and the suicide of his elder brother when he was 23, left him an introverted and taciturn adult.

He showed great mathematical ability as a schoolboy, but studied electrical engineering at Bristol University, as he thought this would lead to gainful employment. In the depression after the First World War this was not forthcoming. One of Dirac’s lecturers offered him a place on the university’s mathematics course and he earned a scholarship for a doctorate at Cambridge.

Dirac’s doctoral thesis built on Werner Heisenberg’s work in the new field of quantum mechanics. In 1928 he developed an equation for the electron that was consistent with quantum mechanics and special relativity. A few years later, he used this ‘Dirac equation’ to predict the existence of antimatter.

In 1933, Dirac was appointed Lucasian Professor of Mathematics at Cambridge and became one of the youngest-ever winners of the Nobel Prize in Physics. During the Second World War he worked as a consultant to Britain’s nuclear bomb project.

Although considered one of the founders of quantum electrodynamics (QED), which explores how light and matter interact, Dirac eventually distanced himself from the emerging discipline and turned his attention to cosmology. One reason for Dirac’s disavowal of QED was that he thought new ideas being developed by others were ugly. He strongly believed that physicists should strive to develop beautiful equations, as these were more likely to be a correct description of the world. After he retired from Cambridge in 1969, Dirac held appointments at the University of Miami and at Florida State University. He is buried in Tallahassee, Florida.

Dirac was appointed to the Order of Merit in 1973. In 1995 a memorial stone, bearing his famous equation, was installed in Westminster Abbey not far from the monument to Isaac Newton.

Further reading:
Graham Farmelo, The Strangest Man: The Hidden Life of Paul Dirac, Quantum Genius (London: Faber and Faber, 2009)

Web links:
Interview with Dirac, 1962, http://www.aip.org/history/ohilist/4575_1.html

Dirac’s Nobel Prize in Physics, 1933, http://nobelprize.org/nobel_prizes/physics/laureates/1933