# Quantum Mechanics

## Volume II: Angular Momentum, Spin, and Approximation Methods

This new edition of the unrivalled textbook introduces concepts such as the quantum theory of scattering by a potential, special and general cases of adding angular momenta, time-independent and time-dependent perturbation theory, and systems of identical particles. The entire book has been revised to take into account new developments in quantum mechanics curricula.

The textbook retains its typical style also in the new edition: it explains the fundamental concepts in chapters which are elaborated in accompanying complements that provide more detailed discussions, examples and applications.

* The quantum mechanics classic in a new edition: written by 1997 Nobel laureate Claude Cohen-Tannoudji and his colleagues Bernard Diu and Franck Laloë

* As easily comprehensible as possible: all steps of the physical background and its mathematical representation are spelled out explicitly

* Comprehensive: in addition to the fundamentals themselves, the book contains more than 170 worked examples plus exercises

Claude Cohen-Tannoudji was a researcher at the Kastler-Brossel laboratory of the Ecole Normale Supérieure in Paris where he also studied and received his PhD in 1962. In 1973 he became Professor of atomic and molecular physics at the Collège des France. His main research interests were optical pumping, quantum optics and atom-photon interactions. In 1997, Claude Cohen-Tannoudji, together with Steven Chu and William D. Phillips, was awarded the Nobel Prize in Physics for his research on laser cooling and trapping of neutral atoms.

Bernard Diu was Professor at the Denis Diderot University (Paris VII). He was engaged in research at the Laboratory of Theoretical Physics and High Energy where his focus was on strong interactions physics and statistical mechanics.

Franck Laloë was a researcher at the Kastler-Brossel laboratory of the Ecole Normale Supérieure in Paris. His first assignment was with the University of Paris VI before he was appointed to the CNRS, the French National Research Center. His research was focused on optical pumping, statistical mechanics of quantum gases, musical acoustics and the foundations of quantum mechanics.

Introduction

Stationary Scattering States. Calculation of the Cross Section

Scattering by a Central Potential. Method of Partial Waves

Complements

ELECTRON SPIN

Introduction

Special Properties of Angular Moment 1/2

Non-Relativistic Description of a Spin 1/2 Particle

Complements

ADDITION OF ANGULAR MOMENTA

Introduction

Addition of Two Spin 1/2's. Elementary Method

Addition of Two Arbitrary Angular Momenta. General Methods

Complements

STATIONARY PERTURBATION THEORY

Description of the Method

Perturbation of a Non-Degenerate Level

Perturbation of a Degenerate Level

Complements

AN APPLICATION OF PERTURBATION THEORY: THE FINE AND HYPERFINE STRUCTURE OF THE HYDROGEN ATOM

Introduction

Additional Terms in the Hamiltonian

The Fine Structure of the N=2 Level

The Hyperfine Structure of the N=1 Level

The Zeeman Effect of the Hyperfine Structure of the 1s Ground State

Complements

APPROXIMATION METHODS FOR TIME-DEPENDENT PROBLEMS

Statement of the Problem

Approximate Solution of the Schrödinger Equation

An Important Special Case: Sinusoidal or Constant Perturbation

Complements

SYSTEMS OF IDENTICAL PARTICLES

Statement of the Problem

Permutation Operators

The Symmetrization Postulate

Discussion

Complements

APPENDICES

Fourier Series and the Fourier Transform

The Dirac "Function"

The Lagrangian and Hamiltonian in Classical Mechanics

Bernard Diu was Professor at the Denis Diderot University (Paris VII). He was engaged in research at the Laboratory of Theoretical Physics and High Energy where his focus was on strong interactions physics and statistical mechanics.

Franck Laloë was a researcher at the Kastler-Brossel laboratory of the Ecole Normale Supérieure in Paris. His first assignment was with the University of Paris VI before he was appointed to the CNRS, the French National Research Center. His research was focused on optical pumping, statistical mechanics of quantum gases, musical acoustics and the foundations of quantum mechanics.