Quantum physics? Nah, just basic counting. Unless Trixie's rabbits exist in a superposition state, they come in whole numbers only. The intermediate value theorem from calculus might suggest she'd pass through 3.3 rabbits going from 2 to 4, but last I checked, rabbits don't come in decimals. What would 0.3 of a rabbit even look like? A fluffy ear? A twitchy nose? Perhaps the professor who wrote this was thinking of Schrödinger's rabbit—simultaneously alive, dead, and apparently, fractional.