Green Functions for Ordered and Disordered Systems


Book Description

The book presents an exposition of Green functions and multiple scattering theory (MST) as presently used in the study of the electronic structure of matter. Ordered, as well as substitutionally disordered systems are discussed. This volume deals with both a tight binding approach to and a first-principles formulation of Green functions and multiple scattering theory. It includes extended discussions on such topics as the coherent potential approximation (CPA), and the use of full cell potentials in applications of MST to the calculation of electronic structure of solids. Special emphasis is given to the derivation of formulae within the angular momentum representation, as well as to problems. The book contains a collection of problems of particular interest to students.




Green's Functions and Ordered Exponentials


Book Description

This book presents a functional approach to the construction, use and approximation of Green's functions and their associated ordered exponentials. After a brief historical introduction, the author discusses new solutions to problems involving particle production in crossed laser fields and non-constant electric fields. Applications to problems in potential theory and quantum field theory are covered, along with approximations for the treatment of color fluctuations in high-energy QCD scattering, and a model for summing classes of eikonal graphs in high-energy scattering problems. The book also presents a variant of the Fradkin representation which suggests a new non-perturbative approximation scheme, and provides a qualitative measure of the error involved in each such approximation. Covering the basics as well as more advanced applications, this book is suitable for graduate students and researchers in a wide range of fields, including quantum field theory, fluid dynamics and applied mathematics.




Green's Functions For Solid State Physicists


Book Description

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./a




Green's Functions and Condensed Matter


Book Description

Presentation of the basic theoretical formulation of Green's functions, followed by specific applications: transport coefficients of a metal, Coulomb gas, Fermi liquids, electrons and phonons, superconductivity, superfluidity, and magnetism. 1984 edition.




Green’s Functions in Quantum Physics


Book Description

In this edition the second and main part of the book has been considerably expanded as to cover important applications of the formalism. In Chap.5 a section was added outlining the extensive role of the tight binding (or equivalently the linear combination of atomic-like orbitals) approach to many branches of solid-state physics. Some additional informa tion (including a table of numerical values) regarding square and cubic lattice Green's functions were incorporated. In Chap.6 the difficult subjects of superconductivity and the Kondo effect are examined by employing an appealingly simple connection to the question of the existence of a bound state in a very shallow potential well. The existence of such a bound state depends entirely on the form of the un perturbed density of states near the end of the spectrum: if the density of states blows up there is always at least one bound state. If the density of states approaches zero continuously, a critical depth (and/or width) of the well must be reached in order to have a bound state. The borderline case of a finite discontinuity (which is very important to superconductivity and the Kondo effect) always produces a bound state with an exponentially small binding energy.




Non-equilibrium Statistical Physics with Application to Disordered Systems


Book Description

This textbook is the result of the enhancement of several courses on non-equilibrium statistics, stochastic processes, stochastic differential equations, anomalous diffusion and disorder. The target audience includes students of physics, mathematics, biology, chemistry, and engineering at undergraduate and graduate level with a grasp of the basic elements of mathematics and physics of the fourth year of a typical undergraduate course. The little-known physical and mathematical concepts are described in sections and specific exercises throughout the text, as well as in appendices. Physical-mathematical motivation is the main driving force for the development of this text. It presents the academic topics of probability theory and stochastic processes as well as new educational aspects in the presentation of non-equilibrium statistical theory and stochastic differential equations.. In particular it discusses the problem of irreversibility in that context and the dynamics of Fokker-Planck. An introduction on fluctuations around metastable and unstable points are given. It also describes relaxation theory of non-stationary Markov periodic in time systems. The theory of finite and infinite transport in disordered networks, with a discussion of the issue of anomalous diffusion is introduced. Further, it provides the basis for establishing the relationship between quantum aspects of the theory of linear response and the calculation of diffusion coefficients in amorphous systems.




Green's Functions in Quantum Physics


Book Description

Of interest to advanced students, this book focuses on Green's functions for obtaining simple and general solutions to basic problems in quantum physics. It demonstrates the unifying formalism of Green's functions across many applications, including transport properties, carbon nanotubes, and photonics and photonic crystals.




Green's Functions with Applications


Book Description

Since its introduction in 1828, using Green's functions has become a fundamental mathematical technique for solving boundary value problems. Most treatments, however, focus on its theory and classical applications in physics rather than the practical means of finding Green's functions for applications in engineering and the sciences. Green's




Disordered Systems


Book Description




Non-equilibrium Green's Functions (NEGF) and Quantum Kinetic Theory


Book Description

In this work we show that Non-equilibrium Green's Function Perturbation Theory (NEGF) is really the overarching perturbative transport theory. It is developed in 3 directions: Landauer-like theory, kinetic theory and Green-Kubo linear response theory. This work generalizes the 2 directions of Landauer-like theory and the kinetic theory. Firstly, NEGF is used to derive phonon-phonon Hedin-like functional derivative equations which generates conserving self energy approximations for phonon-phonon interaction. Secondly, for the Landauer-like theory, using the perturbation expansion, we obtain anharmonic corrections to the ballistic energy current and to the noise associated to the energy current. Along a seperate line, we incooperate high mass disorder into the ballistic energy current formula. The coherent potential approximation (CPA) is found to be compatible with the ballistic energy current expression. Lastly, for the kinetic theory, Wigner coordinates + gradient expansion easily allow the derivation of phonon-phonon correlation corrections to kinetic equations. The main feature of this work is the extremely detailed mathematical explanations.