QUANTUM PHYSICS

A book on quantum physics owes its reader, before anything else, an account of what it is and what it is not.
It is not an encyclopaedia: encyclopaedias flatter completeness and punish understanding. Nor is it a
compendium of recipes for examination day, a genre whose usefulness is real, brief, and fatal to curiosity. It
is, rather, an argument - a single, extended argument that begins with a stove that glowed the wrong colour
and ends, twenty-seven chapters later, with machines that compute upon superpositions and clocks that lose
a second in the lifetime of the universe.
The book is complete in a single volume. It carries the subject from its experimental origins to the
frontiers of quantum information, optics, thermodynamics and technology, across six Parts and twentyseven
chapters. Part I lays the mathematical and physical foundations; Part II erects non-relativistic
quantum mechanics upon them; Part III treats approximation methods and scattering; Part IV extends the
theory to symmetry, path integrals and relativity; Part V develops quantum statistical mechanics and manybody
physics; and Part VI carries the whole into quantum information, computation, optics, open systems,
thermodynamics, and the applications of the quantum in nature and technology. A set of reference
appendices closes the book.
The method throughout is dialectical, in the plain sense of that abused word. Each concept is introduced as a
thesis, confronted with the difficulty or the experiment that refuses it - the antithesis - and resolved into a
structure that preserves what was right in both. This is not a stylistic ornament; it is how the subject actually
developed, and, more importantly, it is how the subject is actually understood. Nobody ever believed
quantum mechanics because it was announced. One believes it because every alternative has been given a fair
trial and has perished honourably in court.
Two promises govern the mathematics. First, nothing falls from the sky: every equation is derived from
stated premises, and where a derivation is deferred to a later chapter, the deferral is confessed in writing.
Second, no algebraic step is skipped on the grounds that the reader could supply it. The reader could; the
reader should not have to. Worked examples are solved completely, including the exact keystroke sequences
for the TI-84 Plus CE calculator; exercises with full solutions close every chapter.
A request. A book of this length, prepared by a single hand, will contain errors despite every care taken
against them. I would be very glad to receive the report of any mistake, ambiguity or obscurity the reader
encounters - typographical, mathematical or conceptual. Every such correction will be acknowledged and
folded into subsequent printings. Whatever errors remain are my own, exclusively, and no reader who
troubles to point one out will find the courtesy unwelcome. Corrections may be sent to me directly at
[email protected].
R. M. M. Edinburgh and São Paulo, 2026