A tutorial on polarized light. Polarized light behaves according to rules that we could think of as belong to classical physics. Nothing too weird happens, and we can make concrete predictions about future observations on the same ray of light. But don’t worry, things are going to get very crazy when we start to look at photos in the next tutorial. This tutorial just paves the way for the vile monstrous insanity that is to follow.
A tutorial on observables and compatibility, using some examples drawn from every day life.
When we’re looking at very small objects, we can’t observe them without disturbing them. The process of measuring the value of a property that we consider them to have, becomes an active process that causes them to manifest that property — a bit like measuring how violent a person is by punching him in the face and seeing if he attacks you or not. One side effect of this is that often measuring one “observable” will disturb the measurement of another observable, in which case we say the two observables are incompatible.