Paul Dirac

A famously quiet English physicist, trained first as an electrical engineer. At Cambridge he turned quickly into one of the most formal and elegant theorists of the century, and he held Newton's old Lucasian professorship.

In 1928 he found a relativistic wave equation for the electron. It automatically gave spin, and it also had solutions of negative energy, which after some wrestling he interpreted in 1931 as a new particle with the electron's mass and opposite charge. Carl Anderson found the positron in cosmic rays in 1932.

His textbook The Principles of Quantum Mechanics (1930) set out the abstract language, including the bra-ket notation, that physicists still use. He also anticipated quantum field theory, and in 1931 showed that a single magnetic monopole somewhere in the universe would explain why electric charge comes in fixed units.

Antimatter was the first prediction of a whole new kind of matter from pure mathematics, a pattern that would repeat through particle physics. Dirac won the 1933 Nobel Prize at thirty-one. His bra-ket notation, |ψ⟩, is the writing system of quantum computing.