Walter Thirring – författare

This volume combines the enlarged and corrected editions of both volumes on classical physics of Thirring's famous course in mathematical physics. With numerous examples and remarks accompanying the text, it is suitable as a textbook for students in physics, mathematics, and applied mathematics. The treatment of classical dynamical systems uses analysis on manifolds to provide the mathematical setting for discussions of Hamiltonian systems, canonical transformations, constants of motion, and pertubation theory. Problems discussed in considerable detail include: nonrelativistic motion of particles and systems, relativistic motion in electromagnetic and gravitational fields, and the structure of black holes. The treatment of classical fields uses the language of differenial geometry throughout, treating both Maxwell's and Einstein's equations in a compact and clear fashion. The book includes discussions of the electromagnetic field due to known charge distributions and in the presence of conductors as well as a new section on gauge theories. It discusses the solutions of the Einstein equations for maximally symmetric spaces and spaces with maximally symmetric submanifolds; it concludes by applying these results to the life and death of stars.

The last decade has seen a considerable renaissance in the realm of classical dynamical systems, and many things that may have appeared mathematically overly sophisticated at the time of the first appearance of this textbook have since become the everyday tools of working physicists. This new edition is intended to take this development into account. I have also tried to make the book more readable and to eradicate errors. Since the first edition already contained plenty of material for a one­ semester course, new material was added only when some of the original could be dropped or simplified. Even so, it was necessary to expand the chap­ ter with the proof of the K-A-M Theorem to make allowances for the cur­ rent trend in physics. This involved not only the use of more refined mathe­ matical tools, but also a reevaluation of the word "fundamental. " What was earlier dismissed as a grubby calculation is now seen as the consequence of a deep principle. Even Kepler's laws, which determine the radii of the planetary orbits, and which used to be passed over in silence as mystical nonsense, seem to point the way to a truth unattainable by superficial observation: The ratios of the radii of Platonic solids to the radii of inscribed Platonic solids are irrational, but satisfy algebraic equations of lower order.

In the past decade the language and methods ofmodern differential geometry have been increasingly used in theoretical physics. What seemed extravagant when this book first appeared 12 years ago, as lecture notes, is now a commonplace. This fact has strengthened my belief that today students of theoretical physics have to learn that language-and the sooner the better. Afterall, they willbe the professors ofthe twenty-first century and it would be absurd if they were to teach then the mathematics of the nineteenth century. Thus for this new edition I did not change the mathematical language. Apart from correcting some mistakes I have only added a section on gauge theories. In the last decade it has become evident that these theories describe fundamental interactions, and on the classical level their structure is suffi­ cientlyclear to qualify them for the minimum amount ofknowledge required by a theoretician. It is with much regret that I had to refrain from in­ corporating the interesting developments in Kaluza-Klein theories and in cosmology, but I felt bound to my promise not to burden the students with theoretical speculations for which there is no experimental evidence. I am indebted to many people for suggestions concerning this volume. In particular, P. Aichelburg, H. Rumpf and H. Urbantke have contributed generously to corrections and improvements. Finally, I would like to thank Dr. 1. Dahl-Jensen for redoing some of the figures on the computer.

This volume combines the enlarged and corrected editions of both volumes on classical physics of Thirring''s famous course in mathematical physics. With numerous examples and remarks accompanying the text, it is suitable as a textbook for students in physics, mathematics, and applied mathematics. The treatment of classical dynamical systems uses analysis on manifolds to provide the mathematical setting for discussions of Hamiltonian systems, canonical transformations, constants of motion, and pertubation theory. Problems discussed in considerable detail include: nonrelativistic motion of particles and systems, relativistic motion in electromagnetic and gravitational fields, and the structure of black holes. The treatment of classical fields uses the language of differenial geometry throughout, treating both Maxwell''s and Einstein''s equations in a compact and clear fashion. The book includes discussions of the electromagnetic field due to known charge distributions and in the presence of conductors as well as a new section on gauge theories. It discusses the solutions of the Einstein equations for maximally symmetric spaces and spaces with maximally symmetric submanifolds; it concludes by applying these results to the life and death of stars.

In the past decade the language and methods ofmodern differential geometry have been increasingly used in theoretical physics. What seemed extravagant when this book first appeared 12 years ago, as lecture notes, is now a commonplace. This fact has strengthened my belief that today students of theoretical physics have to learn that language-and the sooner the better. Afterall, they willbe the professors ofthe twenty-first century and it would be absurd if they were to teach then the mathematics of the nineteenth century. Thus for this new edition I did not change the mathematical language. Apart from correcting some mistakes I have only added a section on gauge theories. In the last decade it has become evident that these theories describe fundamental interactions, and on the classical level their structure is suffi­ cientlyclear to qualify them for the minimum amount ofknowledge required by a theoretician. It is with much regret that I had to refrain from in­ corporating the interesting developments in Kaluza-Klein theories and in cosmology, but I felt bound to my promise not to burden the students with theoretical speculations for which there is no experimental evidence. I am indebted to many people for suggestions concerning this volume. In particular, P. Aichelburg, H. Rumpf and H. Urbantke have contributed generously to corrections and improvements. Finally, I would like to thank Dr. 1. Dahl-Jensen for redoing some of the figures on the computer.

The last decade has seen a considerable renaissance in the realm of classical dynamical systems, and many things that may have appeared mathematically overly sophisticated at the time of the first appearance of this textbook have since become the everyday tools of working physicists. This new edition is intended to take this development into account. I have also tried to make the book more readable and to eradicate errors. Since the first edition already contained plenty of material for a one­ semester course, new material was added only when some of the original could be dropped or simplified. Even so, it was necessary to expand the chap­ ter with the proof of the K-A-M Theorem to make allowances for the cur­ rent trend in physics. This involved not only the use of more refined mathe­ matical tools, but also a reevaluation of the word "fundamental. " What was earlier dismissed as a grubby calculation is now seen as the consequence of a deep principle. Even Kepler''s laws, which determine the radii of the planetary orbits, and which used to be passed over in silence as mystical nonsense, seem to point the way to a truth unattainable by superficial observation: The ratios of the radii of Platonic solids to the radii of inscribed Platonic solids are irrational, but satisfy algebraic equations of lower order.

Die Sprache und die Methoden der modernen Differentialgeometrie sind in der vergangenen Dekade immer mehr in die theoretische Physik eingedrungen. Was vor 15 Jahren, als das Buch zuerst als Vorlesungsskriptum herauskam, noch extravagant erschien, ist heute ein Gemeinplatz. Dies hat mich in der Ansicht gestärkt, daß die Studenten der theoretischen Physik diese Sprache lernen müssen, je eher desto besser. Schließlich werden sie die Professoren des 21. Jahrhunderts sein und es wäre absurd, würden sie dann die Mathematik des 19. Jahrhunderts lehren. Daher habe ich in der neuen Auflage auf dieser Symbolik beharrt, einige Fehler korrigiert und ein Kapi­ tel über Eichtheorien hinzugefügt. Da es sich gezeigt hat, daß sie die fundamentalen Wechselwirkungen beschreiben und ihre Struktur zumindest auf dem klassischen Ni­ veau hinreichend klar ist, scheinen sie mir zur Minimalausrüstung zu gehören, über die jeder Theoretiker verfügen muß. Mit Bedauern mußte ich davon Abstand nehmen, die neueren Entwicklungen der Kosmologie und Kaluza-Klein-artige Theorien aufzu­ nehmen, aber ich fühlte mich an mein ursprüngliches Versprechen gebunden, den Studenten keine theoretischen Spekulationen aufzubürden, für die es keine sichere experimentelle Evidenz gibt. Vielen Physikern bin ich für Hinweise bezüglich dieses Bandes sehr verpflichtet. Insbesondere P. Aichelburg, H. Rumpf und vor allem H. Urbantke haben zahlreiche Korrekturen und Verbesserungen angebracht. I. Dahl-Jensen sei dafür gedankt, daß sie manche nach Gefühl angefertigte Zeichnungen mit dem Computer ins richtige Lot gebracht hat.

In der Quantentheorie werden Observable durch Operatoren im Hilbert-Raum dargestellt. Der dafür geeignete mathematische Rahmen sind die Cx - Algebren, welche Matrizen und komplexe Funktionen verallgemeinern. Allerdings benötigt man in der Physik auch unbeschränkte Operatoren, deren Problematik eigens untersucht werden muß. Dementsprechend werden zunächst mathematische Fragen studiert und dann die Methoden auf atomare Systeme angewandt. Obgleich man außer dem Wasserstoffatom kaum explizit lösbare Probleme findet, lassen sich nicht nur allgemeine qualitative Fragen, etwa bezüglich des Energiespektrums und Streuverhaltens, beantworten, sondern auch quantitativ kann man auch für kompliziertere Systeme für meßbare Größen Schranken teils befriedigender Genauigkeit finden.Inhaltsverzeichnis:Einleitung: Die Struktur der Quantentheorie; Größenordnungen atomarer Systeme.-Die mathematische Formulierung der Quantenmechanik: Lineare Räume; Algebren; Darstellungen im Hilbertraum; Einparametrige Gruppen; Unbeschränkte Operatoren und quadratische Formen.-Quantendynamik: Das Weyl-System; Der Drehimpuls; Die Zeitentwicklung; Der Limes t ; Störungstheorie; Stationäre Streutheorie.-Atomare Systeme: Das Wasserstoffatom; Das H-Atom in äußeren Feldern; Heliumartige Atome; Streuung am einfachen Atom; Komplexe Atome; Kernbewegung und einfache Moleküle.

This fourth edition of selecta of my work on the stability of matter contains recent work on two topics that continue to fascinate me: Quantum electrodynamics (QED) and the Bose gas. Three papers have been added to Part VII on QED. As I mentioned in the preface to the third edition, there must be a way to formulate a non-perturbative QED, presumably with an ultraviolet cutoff, that correctly describes low energy physics, i.e., ordinary matter and its interaction with the electromagnetic field. The new paper VII.5, which “quantizes” the results in V.9, shows that the elementary ‘no-pair’ version of relativistic QED (using the Dirac operator) is unstable when many-body effects are taken into account. Stability can be restored, however, if the Dirac operator with the field, instead of the bare Dirac operator, is used to define an electron. Thus, the notion of a “bare” electron without its self-field is physically questionable.

This fourth edition of selecta of my work on the stability of matter contains recent work on two topics that continue to fascinate me: Quantum electrodynamics (QED) and the Bose gas. Three papers have been added to Part VII on QED. As I mentioned in the preface to the third edition, there must be a way to formulate a non-perturbative QED, presumably with an ultraviolet cutoff, that correctly describes low energy physics, i.e., ordinary matter and its interaction with the electromagnetic field. The new paper VII.5, which “quantizes” the results in V.9, shows that the elementary ‘no-pair’ version of relativistic QED (using the Dirac operator) is unstable when many-body effects are taken into account. Stability can be restored, however, if the Dirac operator with the field, instead of the bare Dirac operator, is used to define an electron. Thus, the notion of a “bare” electron without its self-field is physically questionable.

This edition combines the earlier two volumes on Quantum Mechanics of Atoms and Molecules and on Quantum Mechanics of Large Systems, thus including in a single volume the material for a two-semester course on quantum physics. Since this volume is already quite heavy, I could not include many new results which show how lively the subject is. I just want to mention that inequality (IV:4. 1. l. 1) has been sharpened by T. Weidl by a factor 2][ and the difficult problem 1 of (III:4. 6) has been solved by A. Martin. I have to thank N. Ilieva for the devotion in preparing this new edition. Vienna, November 2001 Walter Thirring Preface to the Second Edition: Quantum Mechanics of Atoms and Molecules Ever since the first edition of this volume appeared in 1980 quantum statistical mechanics has florished. Innumerable results in many areas have been obtained and it would require a series of volumes to do justice to all of them. On the other hand the first edition was already rather crowded with many details so it would not be overburdened any more. Thus I added only one chapter on quantum ergodic theory where one can get the main notions across without too much pain. Nevertheless many subjects treated in the book had splendidely developed ever since and the only way out I could see is to add some recent references which the interested reader can consult.

This edition combines the earlier two volumes on Quantum Mechanics of Atoms and Molecules and on Quantum Mechanics of Large Systems, thus including in a single volume the material for a two-semester course on quantum physics. Since this volume is already quite heavy, I could not include many new results which show how lively the subject is. I just want to mention that inequality (IV:4. 1. l. 1) has been sharpened by T. Weidl by a factor 2][ and the difficult problem 1 of (III:4. 6) has been solved by A. Martin. I have to thank N. Ilieva for the devotion in preparing this new edition. Vienna, November 2001 Walter Thirring Preface to the Second Edition: Quantum Mechanics of Atoms and Molecules Ever since the first edition of this volume appeared in 1980 quantum statistical mechanics has florished. Innumerable results in many areas have been obtained and it would require a series of volumes to do justice to all of them. On the other hand the first edition was already rather crowded with many details so it would not be overburdened any more. Thus I added only one chapter on quantum ergodic theory where one can get the main notions across without too much pain. Nevertheless many subjects treated in the book had splendidely developed ever since and the only way out I could see is to add some recent references which the interested reader can consult.

With this book, Elliott Lieb joins his peers Hermann Weyl and Chen Ning Yang. Weyl''s Selecta was published in 1956, Yang''s Selected Papers in 1983. Lieb''s "Selecta", like its predecessors, gives us the essence of a great mathema­ tical physicist concentrated into one convenient volume. Weyl, Yang and Lieb have much more in common than the accident of this manner of publication. They have in common a style and a tradition. Each of them is master of a for­ midable mathematical technique. Each of them uses hard mathematical ana­ lysis to reach an understanding of physical laws. Each of them enriches both physics and mathematics by finding new mathematical depths in the description of familiar physical processes. The central theme of Weyl''s work in mathematical physics was the idea of symmetry, linking physical invariance-principles with the mathematics of group-theory. One of Yang''s central themes is the idea of a gauge field, linking physical interactions with the mathematics of fibre-bundles. The central theme of Lieb''s papers collected in this book is the classical Thomas-Fermi model of an atom, linking the physical stability of matter with the mathematics of func­ tional analysis. In all three cases, a rather simple physical idea provided the starting-point for building a grand and beautiful mathematical structure. Weyl, Yang and Lieb were not content with merely solving a problem. Each of them was concerned with understanding the deep mathematical roots out of which physical phenomena grow.

The first edition of "The Stability of Matter: From Atoms to Stars" was sold out after a time unusually short for a selecta collection and we thought it ap­ propriate not just to make a reprinting but to include eight new contributionso They demonstrate that this field is still lively and keeps revealing unexpected featureso Of course, we restricted ourselves to developments in which Elliott Lieb participated and thus the heroic struggle in Thomas-Fermi theory where 7 3 5 3 the accuracy has been pushed from Z 1 to Z 1 is not includedo A rich landscape opened up after Jakob Yngvason''s observation that atoms in magnetic fields also are described in suitable limits by a Thomas-Fermi-type theoryo Together with Elliott Lieb and Jan Philip Solovej it was eventually worked out that one has to distinguish 5 regionso If one takes as a dimensionless measure of the magnetic field strength B the ratio Larmor radius/Bohr radius one can compare it with N "'' Z and for each of the domains 4 3 (i) B « N 1 , 4 3 (ii) B "'' N 1 , 4 3 3 (iii) N 1« B « N , 3 (iv) B "'' N , 3 (v) B » N a different version ofmagnetic Thomas-Fermi theory becomes exact in the limit N --+ ooo In two dimensions and a confining potential ("quantum dots") the situation is somewhat simpler, one has to distinguish only (i) B « N, (ii) B "''N,

The second edition of this "selecta" of my work on the stability of matter was sold out and this presented an opportunity to add some newer work on the quantum­ mechanical many-body problem. In order to do so, and still keep the volume within manageable limits, it was necessary to delete a few papers that appeared in the previous editions. This was done without sacrificing content, however, since the material contained in the deleted papers still appears, in abbreviated form, at least, in other papers reprinted here. Seetions VII and VIII are new. The former is on quantum electrodynamics (QED), to which I was led by consideration of stability of the non-relativistic many-body Coulomb problem, as contained in the first and second editions. In particular, the fragility of stability of matter with c1assical magnetic fields, which requires abound on the fine-structure constant even in the non-relativistic case (item V.4), leads to the question of stability in a theory with quantized fields. There are many unresolved problems of QED if one attempts to develop a non­ perturbative theory - as everyone knows. A non-perturbative theory is essential, however, if one is going to understand the stability of the many-body problem, which is the stability of ordinary matter. Some physicists will say that a non­ perturbative QED does not exist - and this might be true in the absence of cutoffs - but an effective theory with cutoffs of a few Mev must exist since matter exists.

This edition combines the earlier two volumes on Quantum Mechanics of Atoms and Molecules and on Quantum Mechanics of Large Systems, thus including in a single volume the material for a two-semester course on quantum physics. Since this volume is already quite heavy, I could not include many new results which show how lively the subject is. I just want to mention that inequality (IV:4. 1. l. 1) has been sharpened by T. Weidl by a factor 2][ and the difficult problem 1 of (III:4. 6) has been solved by A. Martin. I have to thank N. Ilieva for the devotion in preparing this new edition. Vienna, November 2001 Walter Thirring Preface to the Second Edition: Quantum Mechanics of Atoms and Molecules Ever since the first edition of this volume appeared in 1980 quantum statistical mechanics has florished. Innumerable results in many areas have been obtained and it would require a series of volumes to do justice to all of them. On the other hand the first edition was already rather crowded with many details so it would not be overburdened any more. Thus I added only one chapter on quantum ergodic theory where one can get the main notions across without too much pain. Nevertheless many subjects treated in the book had splendidely developed ever since and the only way out I could see is to add some recent references which the interested reader can consult.

The book addresses three major topics in mathematical physics: 1. recent rigorous results in potential theory with appli- cations in particle physics, 2. analyticity in quantum field theory and its applica- tions, and 3. fundamentals and applications of the inverse problem. In addition, the book contains some contributions on questions of general interest in quantum field theory such as nonperturbative solutions of quantum chromodynamics, bifurcation theory applied to chiral symmetry, as well as exactly soluable models. The volume closes with a brief review of geometric approaches to particle physics and a phenomenological discussion of Higgs interactions.

Das vorliegende Lehrbuch will eine zeitgerechte Darstellung der mathema­ tischen Physik bieten. Es entspringt einem viersemestrigen Kurs, den ich, auf einführende Vorlesungen aufbauend, für Mathematiker und Physiker gehalten habe. Um einen für Studierende zumutbaren Umfang zu erreichen, mußte ich eine einschneidende Stoffauswahl treffen. Ich habe mir vorgenommen, nur solche Gebiete zu bringen, in denen, von den Grundgesetzen ausgehend, auf mathematisch lückenlose Weise physikalisch relevante Resultate abgeleitet wer­ den können. Modelle, denen keine realistischen Gesetze zugrunde liegen, können höchstens zur Illustration der mathematischen Sätze dienen, und Theorien, deren Ergebnisse nur über unkontrollierbare Näherungen mit den Grundgesetzen zusammenhängen, wurden beiseite gelassen. So ist der Kurs zu folgenden ftinf­ stündigen Vorlesungen zusammengeschmolzen: I. Klassische dynamische Systeme 11. Klassische Feldtheorie III. Quantenmechanik von Atomen und Molekülen IV. Quantenmechanik großer Systeme. Schmerzlicherweise sind wichtige Teile der Physik, etwa die relativistische Quantentheorie, vom Stadium des Rechenrezeptes noch nicht zu einer mathe­ matisch wohlverstandenen Disziplin gereift und wurden hier nicht aufgenom­ men. Obige Auslese kann natürlich kein Werturteil darstellen, sondern nur einen logisch und didaktisch vertretbaren Versuch. Allgemeine mathematische Kenntnisse werden vorausgesetzt, die verwen­ deten Vokabeln sind zu Beginn schlagwortartig zusammengestellt. Die spezielle­ ren für den Gegenstand benötigten Hilfsmittel werden vorher gebracht, wobei ich mich bemüht habe, die Motivierung für die einzelnen Begriffe klarzustellen und die Reichweite der Aussagen durch Beispiele und Gegenbeispiele abzugren­ zen. An mathematischenMethoden wollte ich das Beste, das zur Zeit am Markt angeboten wird, verwenden.

Der vorliegende Band stellt die klassische Feldtheorie mit den Methoden der modernen Differentialgeometrie dar. Da es sich um die Lösung der Maxwell­ sehen und Einsteinsehen Gleichungen handelt, bringt dies nicht nur begriffliche, sondern auch rechentechnische Vorteile: Das Indexgestrüpp wird durch den Cartanschen Formalismus gelichtet, und die geometrische Bedeutung der Größen tritt hervor. Die Notwendigkeit, den Stoff in der Vorlesung eines Semesters unterzu­ bringen, und die gewünschte Knappheit der Darstellung erforderten eine drasti­ sche Stoffauswahl, und mancher Experte mit diesem oder jenem Steckenpferd wird mir einige Unterlassungssünden nur schwer vergeben. Ich habe versucht, die Tendenz des ersten Bandes fortzuführen und nur das zu bringen, was sich wirk­ lich aus den Grundprinzipien deduzieren läßt; die Teile der Theorie, die W. Pauli gerne als "wishful mathematics" bezeichnet hat, fehlen hier. Damit das Material jedoch nicht zu steril wird, werden die intuitiven Argumente entwickelt, mit deren Hilfe man bei komplizierteren Problemen viele mathematische Lücken überspringt. In der klassischen Feldtheorie kommt man so dem Ideal einer deduktiven Theorie nahe, erreicht es aber nicht ganz. Sowohl in der Elektrodynamik als auch in der Gravitationstheorie treten gelegentlich die von der Singularität des 1/r-Potentials herrührenden Schwierigkeiten wieder auf. Es ist dies wohl charak­ teristisch für jede physikalische Theorie, daß sie bestenfalls weite Bereiche unseres Wissens erfassen kann, aber stets einen unvollendeten Kern hat.

In diesem dritten Teil der mathematischen Physik habe ich versucht, die Quantenmechanik axiomatisch aufzubauen und zu relevanten Anwendungen zu gelangen. In der axiomatischen Literatur gewinnt man manchmal den Eindruck, es gehe vornehmlich darum, durch veredelnde Abstraktionsprozesse die Physik von allen irdischen Schlacken zu befreien und sie dementsprechend dem ein­ fachen Verstand zu entrücken. Hier wird jedoch das Ziel verfolgt, konkrete Resultate zu liefern, die sich mit experimentellen Tatsachen vergleichen lassen. Alles andere ist nur als Hilfsmittel zu betrachten und nach pragmatischen Ge­ sichtspunkten auszuwählen. Aber gerade deswegen scheint es mir geboten, die Methoden der neueren Mathematik heranzuziehen. Nur durch sie gewinnt das Gewebe des logischen Fadens eine glatte Struktur, sonst verfilzt es sich, be­ sonders bei der Theorie unbeschränkter Operatoren, in einem Gestrüpp unüber­ schaubarer Details. Ich habe mich bemüht, dieses mathematische Rüstzeug, welches auch den Grundstock für den nächsten Band bildet, möglichst voll­ ständig zu bringen. Viele Beweise mußten allerdings in Übungsaufgaben unter­ gebracht werden. Das Hauptaugenmerk habe ich darauf gelegt, die üblichen Rechnungen ungewisser Genauigkeit durch solche mit Fehlergrenzen zu er­ setzen, um so die rauhen Sitten der theoretischen Physik zu den kultivierteren der Experimentalphysik zu verfeinern. Die vorangegangenen Bände werden im Text mit (I, ... ) und (II, ... ) zitiert, die allgemeine mathematische Terminologie ist in I zu finden. Die riesige Literatur über den Gegenstand konnte nur sporadisch angeführt werden, der historisch interessierte Leser kann etwas mehr darüber in dem umfassenden Werk von M. Reed und B. Simon finden.

In der Quantentheorie werden Observable durch Operatoren im Hilbert-Raum dargestellt. Der dafür geeignete mathematische Rahmen sind die Cx - Algebren, welche Matrizen und komplexe Funktionen verallgemeinern. Allerdings benötigt man in der Physik auch unbeschränkte Operatoren, deren Problematik eigens untersucht werden muß. Dementsprechend werden zunächst mathematische Fragen studiert und dann die Methoden auf atomare Systeme angewandt. Obgleich man außer dem Wasserstoffatom kaum explizit lösbare Probleme findet, lassen sich nicht nur allgemeine qualitative Fragen, etwa bezüglich des Energiespektrums und Streuverhaltens, beantworten, sondern auch quantitativ kann man auch für kompliziertere Systeme für meßbare Größen Schranken teils befriedigender Genauigkeit finden.Inhaltsverzeichnis:Einleitung: Die Struktur der Quantentheorie; Größenordnungen atomarer Systeme.-Die mathematische Formulierung der Quantenmechanik: Lineare Räume; Algebren; Darstellungen im Hilbertraum; Einparametrige Gruppen; Unbeschränkte Operatoren und quadratische Formen.-Quantendynamik: Das Weyl-System; Der Drehimpuls; Die Zeitentwicklung; Der Limes t ; Störungstheorie; Stationäre Streutheorie.-Atomare Systeme: Das Wasserstoffatom; Das H-Atom in äußeren Feldern; Heliumartige Atome; Streuung am einfachen Atom; Komplexe Atome; Kernbewegung und einfache Moleküle.

Die Sprache und die Methoden der modernen Differentialgeometrie sind in der vergangenen Dekade immer mehr in die theoretische Physik eingedrungen. Was vor 15 Jahren, als das Buch zuerst als Vorlesungsskriptum herauskam, noch extravagant erschien, ist heute ein Gemeinplatz. Dies hat mich in der Ansicht gestärkt, daß die Studenten der theoretischen Physik diese Sprache lernen müssen, je eher desto besser. Schließlich werden sie die Professoren des 21. Jahrhunderts sein und es wäre absurd, würden sie dann die Mathematik des 19. Jahrhunderts lehren. Daher habe ich in der neuen Auflage auf dieser Symbolik beharrt, einige Fehler korrigiert und ein Kapi­ tel über Eichtheorien hinzugefügt. Da es sich gezeigt hat, daß sie die fundamentalen Wechselwirkungen beschreiben und ihre Struktur zumindest auf dem klassischen Ni­ veau hinreichend klar ist, scheinen sie mir zur Minimalausrüstung zu gehören, über die jeder Theoretiker verfügen muß. Mit Bedauern mußte ich davon Abstand nehmen, die neueren Entwicklungen der Kosmologie und Kaluza-Klein-artige Theorien aufzu­ nehmen, aber ich fühlte mich an mein ursprüngliches Versprechen gebunden, den Studenten keine theoretischen Spekulationen aufzubürden, für die es keine sichere experimentelle Evidenz gibt. Vielen Physikern bin ich für Hinweise bezüglich dieses Bandes sehr verpflichtet. Insbesondere P. Aichelburg, H. Rumpf und vor allem H. Urbantke haben zahlreiche Korrekturen und Verbesserungen angebracht. I. Dahl-Jensen sei dafür gedankt, daß sie manche nach Gefühl angefertigte Zeichnungen mit dem Computer ins richtige Lot gebracht hat.