Quantum_ Einstein, Bohr and the Great Debate About the Nature of Reality - Manjit Kumar [135]
Although physicists found it easier to use wave mechanics, no leading theorist agreed with Schrödinger's interpretation of the wave function of a particle as representing the cloud-like distribution of its charge and mass. Undeterred by the widespread acceptance of Born's alternative probability interpretation, Schrödinger highlighted his own and questioned the accepted notion of the 'quantum jump'.
From the moment he received the invitation to speak in Brussels, Schrödinger was acutely aware of the possibility of a clash with the 'matricians'. The discussion began with Bohr asking if a remark about 'difficulties' later in Schrödinger's report implied that a result he had stated earlier was incorrect. Schrödinger dealt with Bohr's inquiry comfortably, only to find Born challenging the correctness of another calculation. Somewhat annoyed, he said it was 'perfectly correct and rigorous and that this objection by Mr Born is unfounded'.21
After a couple of others had spoken, it was Heisenberg's turn: 'Mr Schrödinger says at the end of his report that the discussion he has given reinforces the hope that when our knowledge will be deeper it will be possible to explain and to understand in three dimensions the results provided by the multi-dimensional theory. I see nothing in Mr Schrödinger's calculations that would justify this hope.'22 Schrödinger argued that his 'hope of achieving a three-dimensional conception is not quite utopian'.23 A few minutes later the discussion ended and brought to a close the first part of the proceedings, the presentation of the commissioned reports.
When it was already too late to change the dates, it was discovered that the Académie des Sciences in Paris had chosen Thursday, 27 October to mark the centenary of the death of the French physicist Augustin Fresnel. It was decided that the Solvay meeting would be suspended for a day and a half to allow those wishing to attend the ceremonial event to do so and return for the climax of the conference, a wide-ranging general discussion spread over the last two sessions. Lorentz, Einstein, Bohr, Born, Pauli, Heisenberg and de Broglie were among the twenty who travelled to Paris to honour a kindred spirit.
Amid the distraction of German, French and English voices all seeking permission from Lorentz to speak next, Paul Ehrenfest suddenly got up and walked over to the blackboard and wrote: 'The Lord did there confound the languages of all the earth.' As he returned to his chair there was laughter as his colleagues realised that Ehrenfest was not just referring to the biblical Tower of Babel. The first session of the general discussion began on Friday afternoon, 28 October, with Lorentz making some introductory remarks as he tried to focus minds on the issues of causality, determinism, and probability. Were quantum events caused or not? Or as he put it: 'Could one not maintain determinism by making it an article of faith? Must one necessarily elevate indeterminism to a principle?'24 Offering no further thoughts of his own, Lorentz invited Bohr to address the meeting. As he spoke about the 'epistemological problems confronting us in quantum physics', it was clear to all present that Bohr was attempting to convince Einstein about the correctness of the Copenhagen solutions.25
When the conference proceedings were published in French in December 1928, many mistook Bohr's contribution, then and later, as one of the official reports. When asked for an edited version of his comments for inclusion, Bohr requested that a much-expanded version of his Como lecture, which had been published the previous April, be reprinted in lieu of his remarks. Bohr being Bohr, his request was granted.26
Einstein listened as Bohr outlined his belief that wave-particle duality was an intrinsic feature of nature that was explicable only within the framework of complementarity, that complementarity underpinned the uncertainty principle which exposed the limits of applicability of classical concepts. However, the ability to communicate