Dirac, P(aul) A(drien) M(aurice) 1902-84
English mathematical physicist and Nobel Prize winner

He was born in Bristol, and educated at the universities of Bristol and Cambridge, completing his PhD in 1926. Using the matrix approach of Max Born, Pascual Jordan and Werner Heisenberg, he worked on his own interpretation of quantum mechanics, and in 1928 produced his relativistic wave equation, which explained the electron spin discovered by George Uhlenbeck and Samuel Goudsmit in 1925. This equation had negative energy solutions which he later interpreted as antimatter states (1930). He predicted that a photon could produce an electron-positron pair, which was confirmed experimentally by Carl Anderson in 1932. In 1930 Dirac published the classic work The Principles of Quantum Mechanics and in the same year he was elected FRS. Lucasian Professor of Mathematics at Cambridge (1932-69), he was awarded the Nobel Prize for physics in 1933 with Erwin Schr�dinger for their work in quantum theory. His work on quantum electrodynamics (QED) predicted the existence of the magnetic monopole (not yet discovered), and in 1950 he proposed the idea of particles being not point-like, but string-like, an idea now gaining support following the work of Michael Green, John H Schwarz and Edward Witten. He became Professor of Physics at Florida State University in 1971.

Bibliography: Helge Kragh, Dirac: A Scientific Biography (1990)