From the Preface to the first edition page xiii Preface to the second edition xvii Part I Introduction 1 1 Basic concepts 3 1.1 What is a quantum phase transition? 3 1.2 Nonzero temperature transitions and crossovers 5 1.3 Experimental examples 8 1.4 Theoretical models 9 1.4.1 Quantum Ising model 10 1.4.2 Quantum rotor model l 2 1.4.3 Physical realizations of quantum rotors 14 2 Overview 18 2.1 Quantum field theories 21 2.2 What's different about quantum transitions? 24 Part II A first course 27 3 Classical phase transitions 29 3.1 Mean-field theory 30 3.2 Landau theory 33 3.3 Fluctuations and perturbation theory 34 3.3.1 Gaussian integrals 36 3.3.2 Expansion for susceptibility 39 Exercises 42 4 The renormalization group 45 4.1 Gaussian theory 46 4.2 Momentum shell RG 48 4.3 Field renormalization 53 4.4 Correlation functions 54 Exercises 56 ……
