Task: Explanation
Input (English): Dirac hole theory is a theory in quantum mechanics, named after English theoretical physicist Paul Dirac. 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. Question: When was the English theoretical physicist died who's theory is Dirac hole? Answer: 20 October 1984
Output (English): Dirac hole theory is a theory in quantum mechanics, named after English theoretical physicist Paul Dirac.