(Originally posted on LessWrong, where it’s prettier.)

Learning quantum mechanics involves two things:

1. learning the fundamentals, the nature of the stuff of which Nature is made; and
2. loads of …

• introduce Helmholtz free entropy
• …

Over my life, I’ve learned all these numbers like “mass of a human” (\(\newcommand{\kg}{,\text{kg}} 70\kg\)) and “mass of an electron” (\I9 \cdot 10^{-31}\kg\)) and …

We have two particles, A and B, that are entangled to have spin 0, which means that if we measure A’s spin in one direction (resulting in up/down) and B’s spin in the opposite direction, …