Dirac wave equation

In 1928, Paul Dirac extended the Pauli equation, which described spinning

3650g electrons, to account for special relativity. The result was a theory that dealt properly with events, such as the speed at which an electron

3843b orbits the nucleus, occurring at a substantial fraction of the speed of light. By using the simplest electromagnetic interaction, Dirac was able to predict the value

39sf020a of the magnetic moment associated with the electron's spin, and found the experimentally observed value, which was too large to be that of a spinning charged sphere governed by classical

39sf040 physics. He was able to solve for the spectral lines of the hydrogen atom, and to reproduce from physical first principles Summerland's successful formula for the fine structure of the hydrogen spectrum equations sometimes

39vf512 yielded a negative value for energy, for which he proposed a novel solution: he posited the existence of an anti electron and of a dynamical vacuum. This led to many-particle quantum field theory.