Quantum Physics books

The development of Quantum Physics in the first half of the twentieth century is a fascinating story. In forty short years, while Europe staggered through the Great War and headed inexorably to the Second World War, a group of mainly young physicists developed an entirely new way of understanding the Universe and physical reality. In 1900, the common view among physicists was that the workings of the universe had been largely solved and the only work left to do was to fill in a few gaps but, like many leaps forward in science during human history, solving these 'gaps' led these researchers and experimentalists to develop an entirely new field of physics and a sea-change in how the universe worked. The Classical View of reality - that the universe was something predictable and ultimately completely knowable that functioned whether or not a person was measuring it, was observing it - was destroyed. Instead, the experiments and the mathematics that matched the observed phenomena stated something fundamentally different - that nothing 'physical' existed outside of measurements. Until someone observed or measured the properties of the fundamental particles of the universe, those particles did not exist in any real sense. There was only the probability of those particles existing. This view became known as the Copenhagen Interpretation, after the Physics Institute in Copenhagen and its leader, Neils Bohr.

'Quantum' is an excellent book and a first-rate chronicler of that tumultuous time in physics. It cleverly combines a thorough biography of quantum physics and the (mostly) men who developed the field, along with a strong human story, that of the ongoing tussle between Albert Einstein and Neils Bohr. Einstein may have developed Relativity and transformed our understanding of light, motion and gravity, but he was never happy with the Copenhagen Interpretation of Quantum Physics. He refused to accept that there was nothing outside of our observation of reality, or that the presence of a fundamental particle could be no more than probability, or that the universe's foundations were impossible to know fully. In the latter part of Einstein's life, he watched the physics community move almost to a man to the Copenhagen Interpretation but he did not budge, making his life in physics both an astounding success and a bitter failure.

The book ends with a chapter discussing the puzzles created by quantum physics that have still not been adequately resolved. First and foremost is the question: 'If physical particles only come about through observation, how did the universe start, since there was no one to observe it?' The book also discusses the Schrodinger's Cat thought experiment, much admired by Einstein, and the puzzling questions it asks. Unfortunately, the book doesn't mention at all the conclusion of John Von Neumann and Eugene Wigner, that our minds create reality from the quantum realm, as this does solve the riddle of Schrodinger's Cat. This puzzle is also investigated at length in John Gribbin's excellent book 'Schrodinger's Cat'. Gribbin does a great job of exploring the strange world of quantum physics without drowning the reader in complex mathematics or being so shallow as to distort or lose the important scientific elements. Gribbin also ignores the Neumann-Wigner hypothesis. He lumps for the Many Worlds Hypothesis, although he candidly states that it is a personal preference, rather than a logical decision.

The physicists involved in the development of Quantum Physics were an odd lot, but none was odder than Paul Dirac. Dirac was English, brilliant and quite eccentric. His capacity to remain entirely silent, even in social company, and respond to any question with utter logical sparsity made him almost world-famous. I found Dirac to be a fascinating character; I wish there were more people in the world like him. Farmelo's book is an exhaustive biography. To be honest, I flagged towards the end but that's not a criticism as the author has done a fine job of balancing readability with thoroughness. I'd bet a very large sum of money that the writers of the hit US comedy 'The Big Bang Theory' based their lead character, Sheldon, on Dirac. Dirac was brilliant, odd, but in his own way his eccentricity showed up the daftness of much of life. He may have behaved like a robot sometimes but he was loyal, caring, emotional and just as human as everyone else.