Quantum Mechanics and Atomistic Simulation

An interactive book

The first module of Meccanica quantistica e simulazioni atomistiche, P. Postorino’s Principi di meccanica quantistica, as an interactive book. It is built from my study notes on his weekly slides and the readings posted with them, and is meant to be read instead of them: every slide is here, every result is derived, the slides’ mistakes are corrected and said so, and every section closes with exercises and folded solutions.

So far the book covers weeks 1–4 (28 September – 25 October 2026): the classical tools (oscillators, waves, Fourier, light in vacuum and in matter, probability) and the old quantum theory. Quantum mechanics proper, and G. Zollo’s atomistic simulations in semester II, are added a part at a time as the notes for them are finished.

How to read it

• Drag things. Figures you can move have handles: drag them with a pointer or a finger; with the keyboard, focus a figure, press Enter to pick a handle and the arrow keys to move it (Shift for larger steps). Things snap where something interesting happens, and the text beside the figure says what.
• Colours mean something, the same in the text and in the figures (Notation, constants and colours): $\text{violet}$ for what drives, $\text{dark violet}$ for the response, $\text{orange}$ for what you are looking for, $\text{teal}$ and $\text{pink}$ for real and imaginary parts.
• Dotted links open in place. A reference shows what it names right here; click again to close it.
• Proofs and solutions are folded. Try first, then open.
• Only a few definitions are essential, marked as such. Everything else is built from them (Index of terms).
• “Beyond the lectures” marks what this book adds to the lectures: skipped steps, examples, pictures, results stated on the slides without proof. Everything unmarked is in Postorino’s slides.
• Slide slips are boxes that point out a mistake on a slide and give the correction.
• Extra readings are folded: material from the Moodle readings that goes beyond the slides. The exam asks about what was done in class, so read them for understanding.

The exam

One exam for both modules, examined by G. Zollo. For this module Postorino describes a few written questions on the theory (proofs of theorems, computing wavefunctions, applying the postulates), then an oral discussion of the answers and of anything else covered in the course.

Contents