English theoretical physicist who applied relativity theory to quantum mechanics and predicted the existence of antimatter and the positron (1902-1984)
In relativistic quantum mechanics, the completely filled, negative energy electron state that comprises a vacuum. If a negative energy electron is promoted to a positive energy state, the hole is perceived as a positron
In quantum mechanics, one of two possible ways (the other being Bose-Einstein statistics) in which a system of indistinguishable particles can be distributed among a set of energy states. Each available discrete state can be occupied by only one particle. This exclusiveness accounts for the structure of atoms, in which electrons remain in separate states rather than collapsing into a common state. It also accounts for some aspects of electrical conductivity. This theory of statistical behaviour was developed first by Enrico Fermi and then by P.A.M. Dirac (1926-27). The statistics apply only to particles such as electrons that have half-integer values of spin; the particles are called fermions
born Aug. 8, 1902, Bristol, Gloucestershire, Eng. died Oct. 20, 1984, Tallahassee, Fla., U.S. English mathematician and theoretical physicist. His first major contribution, in 1925-26, was a general and logically simple form of quantum mechanics. About the same time, he developed ideas of Enrico Fermi which led to Fermi-Dirac statistics. He then applied Albert Einstein's special theory of relativity to the quantum mechanics of the electron and showed that the electron must have spin of 1 2 . His theory also revealed new states later identified with the positron. He shared the 1933 Nobel Prize for Physics with Erwin Schrödinger. In 1932 Dirac was appointed to the Lucasian mathematics professorship at the University of Cambridge, a chair once occupied by Isaac Newton. He retired from Cambridge in 1968 and became professor emeritus at Florida State University in 1971