QED: The Strange Theory of Light and Matter by Richard Feynman, 5/5

Most of this book hinges on the bizarre idea of adding amplitude arrows to calculate the probability of certain events happening.  Probability equals the square of the length of an arrow, while the arrow’s direction is determined by the ending position of an imaginary stopwatch’s rotating hand, which turns during the event.  Surprisingly, this unintuitive concept explains a number of phenomena, from iridescence to why light appears to travel in straight lines to the focusing effect lenses have on light.

Of this book’s four chapters, I found the first two to be challenging but reasonably accessible, while the following two became increasingly confusing as the concepts became more complex and Feynman’s patience for explanations seemed to wear thin (if straightforward explanations are even possible, which I almost doubt).  I wish to reread the entire book at a later date and hopefully increase my understanding of the strange concepts it portrays.

[Why I read it: I love reading about quantum physics and have lately been on a Feynman binge.]