Steven Weinberg demonstrates his exceptional insight in this concise introduction to modern quantum mechanics for graduate students. Cover; Contents; Preface; Notation; 1 Historical Introduction; 1.1 Photons; 1.2 Atomic Spectra; 1.3 Wave Mechanics; 1.4 Matrix Mechanics; 1.5 Probabilistic Interpretation; Historical Bibliography; Problems; 2 Particle States in a Central Potential; 2.1 SchroΜdinger Equation for a Central Potential; 2.2 Spherical Harmonics; 2.3 The Hydrogen Atom; 2.4 The Two-Body Problem; 2.5 The Harmonic Oscillator; Problems; 3 General Principles of Quantum Mechanics; 3.1 States; 3.2 Continuum States; 3.3 Observables; 3.4 Symmetries; 3.5 Space Translation; 3.6 Time Translation 3.7 Interpretations of Quantum MechanicsProblems; 4 Spin et cetera; 4.1 Rotations; 4.2 Angular Momentum Multiplets; 4.3 Addition of Angular Momenta; 4.4 The Wigner-Eckart Theorem; 4.5 Bosons and Fermions; 4.6 Internal Symmetries; 4.7 Inversions; 4.8 Algebraic Derivation of the Hydrogen Spectrum; Problems; 5 Approximations for Energy Eigenvalues; 5.1 First-Order Perturbation Theory; 5.2 The Zeeman Effect; 5.3 The First-Order Stark Effect; 5.4 Second-Order Perturbation Theory; 5.5 The Variational Method; 5.6 The Born-Oppenheimer Approximation; 5.7 The WKB Approximation; 5.8 Broken Symmetry Problems6 Approximations for Time-Dependent Problems; 6.1 First-Order Perturbation Theory; 6.2 Monochromatic Perturbations; 6.3 Ionization by an Electromagnetic Wave; 6.4 Fluctuating Perturbations; 6.5 Absorption and Stimulated Emission of Radiation; 6.6 The Adiabatic Approximation; 6.7 The Berry Phase; Problems; 7 Potential Scattering; 7.1 In-States; 7.2 Scattering Amplitudes; 7.3 The Optical Theorem; 7.4 The Born Approximation; 7.5 Phase Shifts; 7.6 Resonances; 7.7 Time Delay; 7.8 Levinson's Theorem; 7.9 Coulomb Scattering; 7.10 The Eikonal Approximation; Problems 8 General Scattering Theory8.1 The S-Matrix; 8.2 Rates; 8.3 The General Optical Theorem; 8.4 The Partial Wave Expansion; 8.5 Resonances Revisited; 8.6 Old-Fashioned Perturbation Theory; 8.7 Time-Dependent Perturbation Theory; 8.8 Shallow Bound States; Problems; 9 The Canonical Formalism; 9.1 The Lagrangian Formalism; 9.2 Symmetry Principles and Conservation Laws; 9.3 The Hamiltonian Formalism; 9.4 Canonical Commutation Relations; 9.5 Constrained Hamiltonian Systems; 9.6 The Path-Integral Formalism; Problems; 10 Charged Particles in Electromagnetic Fields 10.1 Canonical Formalism for Charged Particles10.2 Gauge Invariance; 10.3 Landau Energy Levels; 10.4 The Aharonov-Bohm Effect; Problems; 11 The Quantum Theory of Radiation; 11.1 The Euler-Lagrange Equations; 11.2 The Lagrangian for Electrodynamics; 11.3 Commutation Relations for Electrodynamics; 11.4 The Hamiltonian for Electrodynamics; 11.5 Interaction Picture; 11.6 Photons; 11.7 Radiative Transition Rates; Problems; 12 Entanglement; 12.1 Paradoxes of Entanglement; 12.2 The Bell Inequalities; 12.3 Quantum Computation; Author Index; Subject Index