‎"DIRAC, P.A.M.‎
‎A Theory of Electrons and Protons. - [THE THEORY OF HOLES.]‎

‎London, Royal Society, 1930. Royal 8vo. Recent marbled boards. Extracted from ""Proceedings of the Royal Society in London, Series A, Vol. 126"". pp. 360-365.‎

Reference : 38884

‎First edition of this important paper. ""One of the great difficulties of Dirac's wave equation was from the very beginning, the existance of states of negative energy. The jump from a normal state to such an abnormal state isnot forbidden by any selection rule. Thus, one would expect all electrons to jump into these negative states, contary to experience. The solution of this riddel was given by Dirac'smarvellous theory of holes. Dirac supposed all states of negative energy to be occupied except perhaps a few of small velocity. 'We shall have but an infinite number of electrons in negative-energy states...but if their distribution is exacltly uniform we should expect them to be completely unobseercvable. Only the small departures from uniformity, brought about by some of the negative-energy states being unoccupied, can we hope to obeserve'. He next considers vacant states of 'holes'"" (B.L. van der Waerden).‎