This book shows how the analytic properties in the complex energy plane of the Green's functions of many particle systems account for the physical effects (level shifts, damping, instabilities) characteristic of interacting systems. It concentrates on general physical principles and, while it does not discuss experiments in detail, includes introductions to topics of current research interest, such as singularities (X-ray, Kondo) associated with transient perturbations in an electron gas, the Mott metal-insulator transition in correlated electron systems, and the phenomenon of high Tc superconductivity.This invaluable book grew out of a course of graduate lectures given by S Doniach at the University of London. It will appeal to beginning graduate students in theoretical solid state physics as an introduction to more comprehensive or more specialized texts and also to experimentalists who would like a quick view of the subject. A basic knowledge of solid state physics and quantum mechanics at graduate level is assumed.
Lattice dynamics in the harmonic approximation; lattice dynamics at finite tempertature; the Fenyman-Dyson expansion; the scattering of fermions by a localized pertubation; electrons in the presence of many impurities - the theory of electrical resistance in metals; the interacting electron gas; the magnetic instability of the interacting electron gas; interacting electrons in the atomic limit; transient response of the fermi gas - the X-ray and Kondo problems; conventional superconductivity; electron correlations and heavy fermions; high Tc superconductivity.