Gerald Teschl

Quantum mechanics and the theory of operators on Hilbert space have been deeply linked since their beginnings in the early twentieth century. States of a quantum system correspond to certain elements of the configuration space and observables correspond to certain operators on the space. This book is a brief, but self-contained, introduction to the mathematical methods of quantum mechanics, with a view towards applications to Schrödinger operators. Part 1 of the book is a concise introduction to the spectral theory of unbounded operators. Only those topics that will be needed for later applications are covered. The spectral theorem is a central topic in this approach and is introduced at an early stage. Part 2 starts with the free Schrödinger equation and computes the free resolvent and time evolution. Position, momentum, and angular momentum are discussed via algebraic methods. Various mathematical methods are developed, which are then used to compute the spectrum of the hydrogen atom. Further topics include the nondegeneracy of the ground state, spectra of atoms, and scattering theory. This book serves as a self-contained introduction to spectral theory of unbounded operators in Hilbert space with full proofs and minimal prerequisites: Only a solid knowledge of advanced calculus and a one-semester introduction to complex analysis are required. In particular, no functional analysis and no Lebesgue integration theory are assumed. It develops the mathematical tools necessary to prove some key results in nonrelativistic quantum mechanics. Mathematical Methods in Quantum Mechanics is intended for beginning graduate students in both mathematics and physics and provides a solid foundation for reading more advanced books and current research literature. This new edition has additions and improvements throughout the book to make the presentation more student friendly.

In diesem Lehrbuch werden die mathematischen Grundlagen exakt und dennoch anschaulich und gut nachvollziehbar vermittelt. Sie werden durchgehend anhand zahlreicher Musterbeispiele illustriert, durch Anwendungen in der Informatik motiviert und durch historische Hintergründe oder Ausblicke in angrenzende Themengebiete aufgelockert. Am Ende jedes Kapitels befinden sich Kontrollfragen, die das Verständnis testen und typische Fehler bzw. Missverständnisse ausräumen. Zusätzlich helfen zahlreiche Aufwärmübungen (mit vollständigem Lösungsweg) und weiterführende Übungsaufgaben das Erlernte zu festigen und praxisrelevant umzusetzen. Dieses Lehrbuch ist daher auch sehr gut zum Selbststudium geeignet. Ergänzend wird in eigenen Abschnitten das Computeralgebrasystem Mathematica vorgestellt und eingesetzt, wodurch der Lehrstoff visualisiert und somit das Verständnis erleichtert werden kann.

In diesem Lehrbuch werden die mathematischen Grundlagen exakt und dennoch anschaulich und gut nachvollziehbar vermittelt. Sie werden durchgehend anhand zahlreicher Musterbeispiele illustriert, durch Anwendungen in der Informatik motiviert und durch historische Hintergründe oder Ausblicke in angrenzende Themengebiete aufgelockert. Am Ende jedes Kapitels befinden sich Kontrollfragen, die das Verständnis testen und typische Fehler bzw. Missverständnisse ausräumen. Zusätzlich helfen zahlreiche Aufwärmübungen (mit vollständigem Lösungsweg) und weiterführende Übungsaufgaben das Erlernte zu festigen und praxisrelevant umzusetzen. Dieses Lehrbuch ist daher auch sehr gut zum Selbststudium geeignet. Ergänzend wird in eigenen Abschnitten das Computeralgebrasystem Mathematica vorgestellt und eingesetzt, wodurch der Lehrstoff visualisiert und somit das Verständnis erleichtert werden kann.

This book provides a self-contained introduction to ordinary differential equations and dynamical systems suitable for beginning graduate students. The first part begins with some simple examples of explicitly solvable equations and a first glance at qualitative methods. Then the fundamental results concerning the initial value problem are proved: existence, uniqueness, extensibility, dependence on initial conditions. Furthermore, linear equations are considered, including the Floquet theorem, and some perturbation results. As somewhat independent topics, the Frobenius method for linear equations in the complex domain is established and Sturm-Liouville boundary value problems, including oscillation theory, are investigated. The second part introduces the concept of a dynamical system. The Poincare-Bendixson theorem is proved, and several examples of planar systems from classical mechanics, ecology, and electrical engineering are investigated. Moreover, attractors, Hamiltonian systems, the KAM theorem, and periodic solutions are discussed. Finally, stability is studied, including the stable manifold and the Hartman-Grobman theorem for both continuous and discrete systems. The third part introduces chaos, beginning with the basics for iterated interval maps and ending with the Smale-Birkhoff theorem and the Melnikov method for homoclinic orbits. The text contains almost three hundred exercises. Additionally, the use of mathematical software systems is incorporated throughout, showing how they can help in the study of differential equations. Ancillaries: Corrections -- Updates (Errata)Instructor's Manual

As a partner to Volume 1: Dimensional Continuous Models, this monograph provides a self-contained introduction to algebro-geometric solutions of completely integrable, nonlinear, partial differential-difference equations, also known as soliton equations. The systems studied in this volume include the Toda lattice hierarchy, the Kac-van Moerbeke hierarchy, and the Ablowitz-Ladik hierarchy. An extensive treatment of the class of algebro-geometric solutions in the stationary as well as time-dependent contexts is provided. The theory presented includes trace formulas, algebro-geometric initial value problems, Baker-Akhiezer functions, and theta function representations of all relevant quantities involved. The book uses basic techniques from the theory of difference equations and spectral analysis, some elements of algebraic geometry and especially, the theory of compact Riemann surfaces. The presentation is constructive and rigorous, with ample background material provided in various appendices. Detailed notes for each chapter, together with an exhaustive bibliography, enhance understanding of the main results.

This volume can serve as an introduction and a reference source on spectral and inverse spectral theory of Jacobi operators (i.e., second order symmetric difference operators) and applications of those theories to the Toda and Kac-van Moerbeke hierarchy. Beginning with second order difference equations, the author develops discrete Weyl-Titchmarsh-Kodaira theory, covering all classical aspects, such as Weyl $m$-functions, spectral functions, the moment problem, inverse spectral theory, and uniqueness results. Teschl then investigates more advanced topics, such as locating the essential, absolutely continuous, and discrete spectrum, subordinacy, oscillation theory, trace formulas, random operators, almost periodic operators, (quasi-)periodic operators, scattering theory, and spectral deformations. Utilizing the Lax approach, he introduces the Toda hierarchy and its modified counterpart, the Kac-van Moerbeke hierarchy. Uniqueness and existence theorems for solutions, expressions for solutions in terms of Riemann theta functions, the inverse scattering transform, Backlund transformations, and soliton solutions are derived. This text covers all basic topics of Jacobi operators and includes recent advances. It is suitable for use as a text at the advanced graduate level.