Phase Transitions and Renormalization Group
Jean Zinn-Justin Dapnia, CEA/Saclay, France
and
Institut de Mathinzatiques de Jussieu-Chevaleret, Universitg de Paris VII
OXFORD UNIVERSITY PRESS Contents
1 Quantum field theory and the renormalization group 1 1.1 Quantum electrodynamics: A quantum field theory 3 1.2 Quantum electrodynamics: The Problem of infinities 4 1.3 Renormalization 7 1.4 Quantum field theory and the renormalization group 9 1.5 A triumph of QFT: The Standard Model 10 1.6 Critical phenomena: Other infinities 12 1.7 Kadanoff and Wilson's renormalization group 14 1.8 Effective quantum field theories 16 2 Gaussian expectation values. Steepest descent method 19 2.1 Generating functions 19 2.2 Gaussian expectation values. Wick's theorem 20 2.3 Perturbed Gaussian measure. Connected contributions 24 2.4 Feynman diagrams. Connected contributions 25 2.5 Expectation values. Generating function. Cumulants 28 2.6 Steepest descent method 31 2.7 Steepest descent method: Several variables, generating functions 37 Exercises 40 3 Universality and the continuum limit 45 3.1 Central limit theorem of probabilities 45 3.2 Universality and fixed points of transformations 54 3.3 Random walk and Brownian motion 59 3.4 Random walk: Additional remarks 71 3.5 Brownian motion and path integrals 72 Exercises 75 4 Classical statistical physics: One dimension 79 4.1 Nearest-neighbour interactions. Transfer matrix 80 4.2 Correlation functions 83 4.3 Thermodynamic limit 85 4.4 Connected functions and cluster properties 88 4.5 Statistical models: Simple examples 90 4.6 The Gaussian model 92 x Contents
4.7 Gaussian model: The continuum limit 98 4.8 More general models: The continuum limit 102 Exercises 104 5 Continuum limit and path integrals 111 5.1 Gaussian path integrals 111 5.2 Gaussian correlations. Wick's theorem 118 5.3 Perturbed Gaussian measure 118 5.4 Perturbative calculations: Examples 120 Exercises 124 6 Ferromagnetic systems. Correlation functions 127 6.1 Ferromagnetic systems: Definition 127 6.2 Correlation functions. Fourier representation 133 6.3 Legendre transformation and vertex functions 137 6.4 Legendre transformation and steepest descent method 142 6.5 Two- and four-point vertex functions 143 Exercises 145 7 Phase transitions: Generalities and examples 147 7.1 Infinite temperature or independent spins 150 7.2 Phase transitions in infinite dimension 153 7.3 Universality in infinite space dimension 158 7.4 Transformations, fixed points and universality 161 7.5 Finite-range interactions in finite dimension 163 7.6 Ising model: Transfer matrix 166 7.7 Continuous symmetries and transfer matrix 171 7.8 Continuous symmetries and Goldstone modes 173 Exercises 175 8 Quasi-Gaussian approximation: Universality, critical dimension