Through Two Doors at Once

By Anil Ananthaswamy

Finished reading on October 2, 2019

This is an introduction to quantum mechanics by focusing on the famous “double slit” experiment which reveals one of the most fundamentally bizarre behaviors of light: the observation of individual photon particles makes them behave as if they were waves.

I can’t say that I understood everything that goes on in this book, but the descriptions of some of the experiments themselves make it worth the cost of admission. My favorite involved a team of researchers setting up a double-slit variant on top of mountains in Canary Islands to discover that quantum entanglement seems to, if I understood this correctly, ignore linear time.

The book also goes into the philosophical implications of quantum mechanics: is it true that there is no reality outside of our measurement of it? Is there some sort of barrier between the quantum world and the standard world? These are interesting questions to think about and consider, and it brings to mind a wonderful Feynman quote from QED:

What I am going to tell you about is what we teach our physics students in the third or fourth year of graduate school… It is my task to convince you not to turn away because you don’t understand it. You see my physics students don’t understand it… That is because I don’t understand it. Nobody does.