Quantum_ Einstein, Bohr and the Great Debate About the Nature of Reality - Manjit Kumar [103]
Heisenberg was hardly alone in not being familiar with matrices, but he set about learning the new mathematics with gusto and mastered enough to begin collaborating with Born and Jordan while still in Copenhagen. Heisenberg returned to Göttingen in the middle of October in time to help write the final version of what became known as the Drei-Männer-Arbeit, the 'three-man paper' in which he, Born and Jordan presented the first logically consistent formulation of quantum mechanics – the long-sought-after new physics of the atom. However, there were already reservations being expressed about Heisenberg's initial work. Einstein wrote to Paul Ehrenfest: 'In Göttingen they believe it (I don't).'58 Bohr believed it was 'a step probably of fundamental importance' but 'it has not yet been possible to apply [the] theory to questions of atomic structure'.59 While Heisenberg, Born and Jordan had been concentrating on developing the theory, Pauli had been busy using the new mechanics to do just that. By early November, while the 'three-man paper' was still being written, he had successfully applied matrix mechanics in a stunning tour de force. Pauli had done for the new physics what Bohr had done for the old quantum theory – reproduced the line spectrum of the hydrogen atom. For Heisenberg, to add insult to injury, Pauli had also calculated the Stark effect – the influence of an external electric field on the spectrum. 'I myself had been a bit unhappy that I could not succeed in deriving the hydrogen spectrum from the new theory', Heisenberg recalled.60 Pauli had provided the first concrete vindication of the new quantum mechanics.
'The Fundamental Equations of Quantum Mechanics' read the title. Born had been in Boston for a nearly a month, as part of a five-month lecture tour of the United States, when one December morning he opened his post and received 'one of the greatest surprises' of his scientific life.61 As he read the paper by one P.A.M. Dirac, a senior research student at Cambridge University, Born realised that 'everything was perfect in its way'.62 Even more remarkably, Born soon discovered that Dirac had sent his paper to the Proceedings of the Royal Society containing the nuts and bolts of quantum mechanics a whole nine days before the 'three-man paper' was finished. Who was Dirac and how had he done it, wondered Born?
Paul Adrien Maurice Dirac was 23 years old in 1925. The son of a Swiss, French-speaking father, Charles, and an English mother, Florence, he was the second of three children. His father was such an overbearing and dominant figure that when he died in 1935, Dirac wrote: 'I feel much freer now.'63 It was the trauma of having to remain silent in the presence of his father, a teacher of French, as he grew up that made Dirac a man of few words. 'My father made the rule that I should only talk to him in French. He thought it would be good for me to learn French in that way. Since I found that I couldn't express myself in French, it was better for me to stay silent than to talk in English.'64 Dirac's preference for silence, the legacy of a deeply unhappy childhood and adolescence, would become legendary.
Although interested in science, in 1918, Dirac acted on his father's advice and enrolled to study electrical engineering at the University of Bristol. Three years later, despite graduating with a first-class honours degree, he could not find a job as an engineer. With his employment prospects looking bleak as Britain's post-war depression continued, Dirac accepted the offer of free tuition for two years to study mathematics back at his old university. He would rather have