For the week of the conference all that delegates could think and talk about was Bohr’s quantum mechanics. It was a truly formidable theory. Over the week the final show down played out between Niels Bohr and his arch-rival, Albert Einstein.
Einstein hated quantum mechanics and every morning he’d come to Bohr with an argument he felt picked a hole in the new theory. Bohr would go away very disturbed and think very hard about it and by the end of the day he’d come back with a counter argument that dismissed Einstein’s criticism. And this happened day after day until by the end of the conference Bohr had brushed aside all of Einstein’s criticisms and Bohr was regarded as having been victorious. And with that, his vision of the atom, which became known as the Copenhagen Interpretation, was suddenly at the very heart of atomic physics.
At the end of the conference they all gather for the team photo. Never before or since have so many great names of physics been together in one place. At the front the elder statesman of physics Hendrik Lorentz, flanked on either side by Madame Curie and Albert Einstein. Einstein’s looking rather glum because he’s lost the argument. Louis de Broglie has also failed to convince the delegates of his views. Victory goes to Neils Bohr. He’s feeling very pleased with himself. Next to him one of the unsung heroes of quantum mechanics the German Max Born who developed so much of the mathematics. And behind him the two young disciples of Bohr, Werner Heisenberg and Wolfgang Pauli. Pauli is looking rather smugly across at Schrödinger, like the cat who’s got the milk.
This was the moment in physics when it all changed. The old guard was replaced by the new. Chance, a probability became interwoven into the fabric of nature itself and we could no longer describe atoms in terms of simple pictures but only using pure abstract mathematics. The Copenhagen view had been victorious.