Louisa Gilder

Quantum mechanics and the phenomenon of entanglement, where particles that are created together or exist in close proximity have certain basic features (their quantum state) which either cannot be described independently of each other or do not exist independently of each other even if the particles become separated by an arbitrarily large distance, are very complex topics. I don't know if you can really learn any basic thing about them by reading this book.

The author has attempted to write a conceptual history of the idea of entanglement. She describes her technique in the preface, creating dialogues from the famous participants remembered spoken comments and their contemporary relevant written comments. The result is interesting, but much of it is not very closely related to her topic and, since it is mostly just mention of arguments among the discoverers/creators of quantum physics without the mathematics, it can be somewhat vacuous. Some of the dialogues, especially the historically earlier ones, read like a bad play.

The book is structured around a particular discovery or concept of a famous Scottish physicist named John Bell, called Bell’s theorem or Bell’s inequality. This theorem or inequality is mentioned fairly frequently in the book, but descriptions are vague. It is probably an impossible task to explain this topic to a large mathematically naive readership. The problem is, of course, quantum theory itself. As Chris Fuchs is quoted in the book,

When I was in junior high school, I sat down with Martin Gardner's book 'Relativity for the Million' and came away with an understanding of the subject that sustains me even today. The concepts were strange to my everyday world, but they were clear enough that I could get a grasp of them knowing little more mathematics than arithmetic. One should expect nothing less for a proper foundation to the quantum. Until we can explain the essence of the theory to a junior high school student ... –the essence, not the mathematics – and have them walk away with a deep lasting memory, I well believe we will have not understood a thing about quantum foundations.

The author’s analogies and explanations are sometimes lacking, for example when she feels the need to parenthetically define a function as (part of an equation), but the original Einstein gedanken experiment that was later described in the EPR paper, and some of the recent experiments in entanglement are well described.

None of this means that there isn’t a lot of interesting stuff here, mostly about the physicists' interactions and private lives. One approach might be to read this book as a supplement to another more technical one on quantum physics. I found reading the Wikipedia entries on quantum entanglement and Bell’s theorem to be very helpful.… (plus d'informations)

While quantum mechanics has been able to answer many practical questions about the structure and bonding of atoms, molecules, nuclei, and even subatomic particles, it still does not adequately yield its own ultimate meaning. The ability of an electron to be in more than one place at once, to appear on both sides of a node, and to have no defined boundary are only the "down payments" for the mysteries of quantum mechanics, about which even its developers were conflicted. I was fortunate to have heard a David Mermin lecture based on his famous Physics Today (1985 38(4) 38) article, "Is the Moon There When Nobody Looks?", an understandable introduction to the disturbing consequences of what is called "entanglement" that is still well worth reading. The first part of Gilder's description of modern quantum mechanics does not break much new ground, but this reader tuned in when she began to describe David Bohm and his "hidden variables" attempts to find a deterministic interpretation. She builds her history through real correspondence and imagined but plausible conversations between the likes of J. M. Jauch, John Bell and interviews with Nicolas Gisin and Anton Zeilinger. She may have filled some gaps with conversations that never occurred, but through that, she has made clear the disturbing truth about the meaning of quantum mechanics.… (plus d'informations)