Paul A.M. Dirac (1902-1984) was a British theoretical physicist who helped develop mathematical expressions of relativistic quantum mechanics. His scientific philosophy was this: "Physical laws should have mathematical beauty and simplicity."
Dirac developed a equation of motion for the wavefunction of the electron based on relativity. Dirac to predicted the existence of the positron, the electron's antiparticle, which was subsequently discovered by Carl Anderson in 1932. Dirac was the founder of quantum electrodynamics.
Dirac published the "Principles of Quantum Mechanics" in 1930, which introduced the widely used delta function and bra-ket notation. Inspired in part by this book, the physicist Richard Feynman later proposed a path integral formulation of quantum mechanics in 1948.