Thursday, June 11, 2015

Oh What an Entangled Web We Weave...

I looked up "entanglement" in the indexes of half a dozen quantum mechanics texts I have around here. Didn't find it. The spooky quantum entanglement that so bothered Einstein doesn't feature heavily enough in any of them to make the index. Quantum Mechanics: The Theoretical Minimum isn't like that. Leonard Susskind and Art Friedman put quantum entanglement at the center of their book. For them, entanglement is the most novel and one of the most important features of quantum, as well as one that is consistently neglected in textbooks.

I happened upon the book more or less by accident. I was wandering through a bookstore with one of my old graduate school office mates, arguing, as usual, about Bell's Theorem, realism in quantum mechanics, and so on. I suddenly realized that I really was a bit unclear on exactly what was meant by quantum entanglement. Since it was a bookstore and we were in the physics section, I looked around for a QM book and there was Susskind - the book, that is. I found a pretty good definition, and much more, so I bought the book.

It's a textbook of sorts, but not a conventional one. It has equations and even problems, but the concern is very clearly with presentation of the fundamental ideas in the simplest and clearest fashion possible. I've only read a few parts so far, so I'm not going to make any definitive declarations, but so far I really like it. If you've had some exposure to quantum mechanics, even a long time ago, you can pretty much read it like a novel.

If you haven't, a little calculus is needed, and some exposure to linear algebra would be nice, but the latter is developed in the text. Apparently some classical mechanics is used later in the book, but he begins with the simplest possible quantum system, a spin one-half particle, and develops the formalism and ideas from there.

So far, I think it looks like a great book to clarify quantum ideas, well-suited to the student who is about to take quantum or who has already completed a course or two but having trouble fitting it all together. It also looks good for old fogies who have forgotten a lot.