Author Manjit Kumar wrote in the Prologue to this 2008 book, “Whereas the name Einstein is a byword for scientific genius, Niels Bohr was, and remains, less well known. Yet to his contemporaries he was every inch the scientific giant… When Einstein and Bohr first met in...
Author Manjit Kumar wrote in the Prologue to this 2008 book, “Whereas the name Einstein is a byword for scientific genius, Niels Bohr was, and remains, less well known. Yet to his contemporaries he was every inch the scientific giant… When Einstein and Bohr first met in Berlin in 1920, each found an intellectual sparring partner who would, without bitterness or rancour, push and prod the other into refining and sharpening his thinking about the quantum. It is through them and some of those gathered at Solvay 1927 that we capture the pioneering years of quantum physics… Without the quantum, the world we live in would be very different. Yet for most of the twentieth century, physicists accepted that quantum mechanics denied the existence of a reality beyond what was measured in their experiments.” (Pg. xii-xiii)
He notes, “Years after [Max] Planck’s death in 1947, at the age of 89, his former student and colleague James Franck recalled watching his hopeless struggle ‘to avoid quantum theory, [to see] whether he could not at least make the influence of quantum theory as little as it could possibly be.’ It was clear to Franck that Planck ‘was a revolutionary against his own will’ who ‘finally came to the conclusion, “It doesn’t help. We have to live with quantum theory. And believe me, it will expand.’ It was a fitting epitaph for a reluctant revolutionary.” (Pg. 29)
He notes, “Over a quarter of a century, the developments in quantum physics… were the product of an unhappy marriage of quantum concepts and classical physics. It was a union that by 1925 was increasingly under strain. ‘The more successes the quantum theory enjoys, the more stupid it looks,’ Einstein had written as early as May 1912. What was needed was a new theory, a new mechanics of the quantum world… Given the pivotal role of young physicists in making the revolution that shaped the modern world, these were the years of knabenphysik---‘boy physics.’” (Pg. 153)
He points out, “In December 1926, Einstein had expressed his growing disquiet at the rejection of causality and determinism in a letter to Born: ‘Quantum mechanics is certainly imposing. But an inner voice tells me that it is not yet the real thing. The theory says a lot, but does not really bring us any closer to the secret of the “old one.” I, at any rate, am convinced that He is not playing at dice.’ As the battle lines were being drawn, Einstein was unwittingly the inspiration for a stunning breakthrough, one of the greatest and profoundest achievements in the history of the quantum---the uncertainty principle.” (Pg. 224)
He explains, Bohr never used the term the ‘Copenhagen interpretation,’ nor did anyone else until Heisenberg in 1955. Yet from a handful of adherents it quickly spread so that for most physicists the ‘Copenhagen interpretation of quantum mechanics’ because synonymous with quantum mechanics. Three factors lay behind this rapid dissemination and acceptance of the ‘Copenhagen spirit.’ The first was the pivotal role of Bohr and his institute… Secondly, around the time of Solvay 1927 a number of professorships became vacant. Those who had helped create the new physics filled nearly all of these… Lastly, despite their differences, Bohr and his younger associates always presented a united front against all challenges to the Copenhagen interpretation.” (Pg. 276-277)
He states, “One possible reason for the misunderstanding may be that Einstein first said that God ‘is not playing at dice’ in December 1926 when he tried to convey to Born his unease at the role of probability and chance in quantum mechanics and the rejection of causality and determinism. Pauli, however, understood that Einstein’s objections went far beyond the theory being expressed in the language of probability. ‘In particular it seems to me misleading to bring the concept of determinism into the dispute with Einstein,’ he warned Born. ‘At the heart of the problem,’ wrote Einstein in 1950 of quantum mechanics, ‘is not so much the question of causality but the question of realism.’ For years he had hoped that he ‘may yet work out the quantum puzzle without having to renounce the representation of reality.’ For the man who discovered relativity, the reality had to be local, with no place for faster-than-light influences. The violation of Bell’s inequality meant that if he wanted a quantum world that existed independently of observers, then Einstein would have had to give up locality.” (Pg. 353)
He concludes, “In December 1900, classical physics had a place for everything and almost everything in its place. Then Max Planck stumbled across the quantum, and physicists are still struggling to come to terms with it. Fifty long years of ‘conscious brooding,’ said Einstein, had not brought him any closer to understanding the quantum. He kept trying to the end, taking solace in the words of the German playwright and philosopher Gotthold Lessing: ‘The aspiration
to truth is more precious than its assured possession.” (Pg. 360)
There is a great deal of interesting “background” information about all of the personalities involved in the development of quantum physics; this book will thus be of keen interest to anyone studying the history of this subject.