Bananaworld: quantum mechanics for primates

In spite of the title, Bananaworld is intended to be a serious book about quantum entanglement: what it is, what people have said about it, and what you can do with it. The idea was to bring out the difference between classical and quantum mechanics by considering the extent to which it is possible to simulate the correlation of a Popescu-Rohrlich (PR) nonlocal box with various resources, quantum or classical. Bell’s nonlocality theorem is essentially a proof that the probability of a successful simulation with classical resources is at most .75, while the probability with quantum resources increases to about .85. The bananas were a way of showing the banality of this hypothetical correlation for an imagined pair of PR-entangled bananas in terms of a correlation between peeling from either of the two ends of a banana and two possible tastes. As an afterthought, I added a final chapter about interpretations of quantum mechanics and the measurement problem. I wasn’t satisfied with my take on this in the first edition of the book, so I re-wrote the chapter for the revised paperback edition. I’ll talk about what I was trying to do in the book, and my current view about the issues in the final, still problematic chapter.