Paul Dirac

Paul Adrien Maurice Dirac (1902–1984) served as Lucasian Professor of Mathematics at Cambridge. In 1928, Dirac formulated the relativistic wave equation for the electron (the Dirac equation), which was completely compatible with Einstein's special relativity.

The equation naturally explained electron spin and predicted the existence of negative-energy states, which Dirac interpreted as antiparticles of identical mass but positive charge. In 1932, Carl Anderson discovered the positron, confirming Dirac's prediction. Dirac introduced bra-ket notation (⟨bra|ket⟩) and shared the 1933 Nobel Prize in Physics with Erwin Schrödinger.