Dirac hole theory is a theory in quantum mechanics, named after English theoretical physicist Paul Dirac, who introduced it in 1929. The theory poses that the continuum of negative energy states, that are solutions to the Dirac equation, are filled with electrons, and the vacancies in this continuum (holes) are manifested as positrons with energy and momentum that are the negative of those of the state. The discovery of the positron in 1929 gave a considerable support to the Dirac hole theory.