$$\require{cancel}$$

# 1: Reviewing Elementary Stuff

• 1.1: Breakdown of Classical Mechanics
• 1.2: Early Quantum Mechanics
ou don’t need to know the historical facts, of course, but some of the physics arguments are worth recalling—for example, Bohr’s derivation of the Rydberg constant from his model atom. If you’re interested in more details.
• 1.3: Wave Equations, Wavepackets and Superposition
There is no rigorous derivation of Schrödinger’s equation from previously established theory, but it can be made very plausible by thinking about the connection between light waves and photons, and construction an analogous structure for de Broglie’s waves and electrons (and, later, other particles).
• 1.4: The Uncertainty Principle
The wave nature of particles implies that we cannot know both position and momentum of a particle to an arbitrary degree of accuracy.
• 1.5: Electron in a Box
The best way to gain understanding of Schrödinger’s equation is to solve it for various potentials. The simplest is a one-dimensional “particle in a box” problem.

Thumbnail: Propagation of de Broglie waves in 1d—real part of the complex amplitude is blue, imaginary part is green. The probability (shown as the color opacity) of finding the particle at a given point x is spread out like a waveform, there is no definite position of the particle. (Public Domain; Maschen)