GraduateTextsinMathematicsGTMBrian C. HallQuantumTheory forMathematiciansSpringer
Graduate Texts in Mathematics Brian C. Hall Quantum Theory for Mathematicians
GraduateTextsinMathematicsSeries Editors:SheldonAxlerSan Francisco State University, SanFrancisco, CA, USAKennethRibetUniversityofCalifomia,Berkeley,CA,USAAdvisory Board:ColinAdams,WilliamsCollege,Williamstown,MA,USAAlejandroAdem,UniversityofBritishColumbia,Vancouver,BC,CanadaRuthCharney,BrandeisUniversityWaltham,MA,USAIreneM.Gamba,TheUniversityofTexas atAustin,Austin,TX,USARoger E.Howe,YaleUniversity,NewHaven,CT,USADavid Jerison,MassachusettsInstituteofTechnologyCambridge,MA,USAJeffreyC.Lagarias,UniversityofMichigan,AnnArbor,Ml,USAJillPipher,BrownUniversity,Providence,RI,USAFadil Santosa,University ofMinnesota,Minneapolis,MN,USAAmieWilkinson,UniversityofChicago,Chicago,IL,USAGraduate Texts in Mathematics bridge the gap between passive study andcreative understanding, offering graduate-level introductions to advanced topicsin mathematics.The volumes are carefully written as teaching aids and highlightcharacteristic features of the theory.Although these books arefrequently used astextbooks in graduate courses,they are also suitablefor individual study.Forfurthervolumes:http://www.springer.com/series/136
Graduate Texts in Mathematics Series Editors: Sheldon Axler San Francisco State University, San Francisco, CA, USA Kenneth Ribet University of California, Berkeley, CA, USA Advisory Board: Colin Adams, Williams College, Williamstown, MA, USA Alejandro Adem, University of British Columbia, Vancouver, BC, Canada Ruth Charney, Brandeis University, Waltham, MA, USA Irene M. Gamba, The University of Texas at Austin, Austin, TX, USA Roger E. Howe, Yale University, New Haven, CT, USA David Jerison, Massachusetts Institute of Technology, Cambridge, MA, USA Jeffrey C. Lagarias, University of Michigan, Ann Arbor, MI, USA Jill Pipher, Brown University, Providence, RI, USA Fadil Santosa, University of Minnesota, Minneapolis, MN, USA Amie Wilkinson, University of Chicago, Chicago, IL, USA Graduate Texts in Mathematics bridge the gap between passive study and creative understanding, offering graduate-level introductions to advanced topics in mathematics. The volumes are carefully written as teaching aids and highlight characteristic features of the theory. Although these books are frequently used as textbooks in graduate courses, they are also suitable for individual study. For further volumes: http://www.springer.com/series/136
Brian C.HallDepartment of MathematicsUniversityofNotreDameNotre Dame, IN, USAISSN0072-5285ISBN 978-1-4614-7115-8ISBN978-1-4614-7116-5 (eBook)DOI10.1007/978-1-4614-7116-5Springer New York Heidelberg Dordrecht LondonLibrary of Congress Control Number: 2013937175Mathematics Subject Classification: 81-01,81S05,81R05,46N50,81Q20, 81Q10,81S40,53D50SpringerScience+Business Media NewYork2013This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or partof the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations,recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission orinfomation storage and retrieval, electronic adaptation, computer software, or by similar or dissim-ilar methodology now known or hereafter developed. Exempted from this legal reservation are briefexcerpts in connection with reviews or scholarly analysis or material supplied specifically for the pur-pose of being entered and executed on a computer system, for exclusive use by the purchaser of thework. Duplication of this publication or parts thereof is permitted only under the provisions of theCopyright Law of the Publisher's location, in its current version, and permission for use must alwaysbe obtained from Springer. Pemissions for use may be obtained through RightsLink at the CopyrightClearance Center. Violations are liable to prosecution under the respective Copyright Law.The use of general descriptive names, registered names, trademarks, service marks, etc. in this publi-cation does not imply, even in the absence of a specific statement, that such names are exempt fromthe relevant protective laws and regulations and therefore free for general use.While the advice and information in this book are believed to be true and accurate at the date ofpublication, neither the authors nor the editors nor the publisher can accept any legal responsibility forany errors or omissions that may be made. The publisher makes no warranty, express or implied, withrespect to the material contained herein.Printed on acid-free paperSpringer is part of Springer Science+Business Media (www.springer.com)
Brian C. Hall Department of Mathematics University of Notre Dame Notre Dame, IN, USA ISSN 0072-5285 ISBN 978-1-4614-7115-8 ISBN 978-1-4614-7116-5 (eBook) DOI 10.1007/978-1-4614-7116-5 Springer New York Heidelberg Dordrecht London Library of Congress Control Number: 2013937175 Mathematics Subject Classification: 81-01, 81S05, 81R05, 46N50, 81Q20, 81Q10, 81S40, 53D50 © Springer Science+Business Media New York 2013 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. Exempted from this legal reservation are brief excerpts in connection with reviews or scholarly analysis or material supplied specifically for the purpose of being entered and executed on a computer system, for exclusive use by the purchaser of the work. Duplication of this publication or parts thereof is permitted only under the provisions of the Copyright Law of the Publisher’s location, in its current version, and permission for use must always be obtained from Springer. Permissions for use may be obtained through RightsLink at the Copyright Clearance Center. Violations are liable to prosecution under the respective Copyright Law. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. While the advice and information in this book are believed to be true and accurate at the date of publication, neither the authors nor the editors nor the publisher can accept any legal responsibility for any errors or omissions that may be made. The publisher makes no warranty, express or implied, with respect to the material contained herein. Printed on acid-free paper Springer is part of Springer Science+Business Media (www.springer.com)
PrefaceIdeas from quantumphysics playimportant roles in many parts of modernmathematics. Many parts of representation theory, for example, are moti-vated by quantum mechanics, including the Wigner-Mackey theory of in-duced representations, the Kirillov-Kostant orbit method, and, of course,quantumgroups.TheJones polynomial inknot theory,the Gromov-Witteninvariants in topology,and mirror symmetry in algebraic topology are othernotable examples.The awarding of the 1990 Fields Medal to Ed Witten, aphysicist, gives an idea of the scope of the influence of quantum theory inmathematics.Despite the importance of quantum mechanics to mathematics, there isno easy way for mathematicians to learn the subject. Quantum mechan-ics books in the physics literature are generally not easily understood bymost mathematicians. There is, of course, a lower level of mathematicalprecision in such books than mathematicians are accustomed to. In addi-tion, physics books on quantum mechanics assume knowledge of classicalmechanics that mathematicians often do not have. And, finally, there is asubtle difference in “"culture"differences in terminology and notation-that can make reading the physics literature like reading a foreign languagefor themathematician.Thereare few books that attempt to translate quan-tum theory into terms that mathematicians can understand.This book is intended as an introduction to quantum mechanics for math-ematicians with little prior exposure to physics.The twin goals of the bookare (1) to explain the physical ideas of quantum mechanics in languagemathematicians will be comfortable with, and (2) to develop the neces-sary mathematical tools to treat those ideas in a rigorous fashion. I havevii
Preface Ideas from quantum physics play important roles in many parts of modern mathematics. Many parts of representation theory, for example, are motivated by quantum mechanics, including the Wigner–Mackey theory of induced representations, the Kirillov–Kostant orbit method, and, of course, quantum groups. The Jones polynomial in knot theory, the Gromov–Witten invariants in topology, and mirror symmetry in algebraic topology are other notable examples. The awarding of the 1990 Fields Medal to Ed Witten, a physicist, gives an idea of the scope of the influence of quantum theory in mathematics. Despite the importance of quantum mechanics to mathematics, there is no easy way for mathematicians to learn the subject. Quantum mechanics books in the physics literature are generally not easily understood by most mathematicians. There is, of course, a lower level of mathematical precision in such books than mathematicians are accustomed to. In addition, physics books on quantum mechanics assume knowledge of classical mechanics that mathematicians often do not have. And, finally, there is a subtle difference in “culture”—differences in terminology and notation— that can make reading the physics literature like reading a foreign language for the mathematician. There are few books that attempt to translate quantum theory into terms that mathematicians can understand. This book is intended as an introduction to quantum mechanics for mathematicians with little prior exposure to physics. The twin goals of the book are (1) to explain the physical ideas of quantum mechanics in language mathematicians will be comfortable with, and (2) to develop the necessary mathematical tools to treat those ideas in a rigorous fashion. I have vii
viiPrefaceattempted to give a reasonably comprehensive treatment of nonrelativisticquantum mechanics, including topics found in typical physics texts (e.g.,theharmonic oscillator,the hydrogen atom, and the WKB approximation)as well as more mathematical topics (e.g., quantization schemes, the Stone-von Neumann theorem, and geometric quantization).Ihave also attemptedto minimize the mathematical prerequisites.I do not assume, for example,any prior knowledge of spectral theory or unbounded operators, but pro-vide a full treatment of those topics in Chaps.6 through 10 of the text.Similarly, I do not assume familiarity with the theory of Lie groups andLie algebras, but provide a detailed account of those topics in Chap.16.Whenever possible, I provide full proofs of the stated results.Most of the text will be accessible to graduate students in mathematicswho have had a first course in real analysis, covering the basics of L? spacesand Hilbert spaces. Appendix A reviews some of the results that are used inthe main body of the text. In Chaps.21 and 23, however, I assume knowl-edge of the theory of manifolds.I have attempted to provide motivation formany of the definitions and proofs in the text, with the result that thereis a fair amount of discussion interspersed with the standard definition-theorem-proof style of mathematical exposition. There are exercises at theend of each chapter,making the book suitable for graduate courses as wellas forindependentstudy.In comparison to thepresent work, classics such as Reed and Simon [34]and Glimm and Jaffe[14],along with therecentbook of Schmidgen [35],are more focused on the mathematical underpinnings of the theory thanon the physical ideas. Hannabuss's text [22] is fairly accessible to math-ematicians, but-despite the word "graduate" in the title of the series-uses an undergraduate level of mathematics. The recent book of Takhtajan[39], meanwhile, has an expository bent to it, but provides less physicalmotivation and is less self-contained than the present book. Whereas, forexample, Takhtajan begins with Lagrangian and Hamiltonian mechanicson manifolds, I begin with"low-tech"classical mechanics on the real line.Similarly, Takhtajan assumes knowledge of unbounded operators and Liegroups, while I provide substantial expositions of both of those subjects.Finally, there is the work of Folland [13], which I highly recommend, butwhich deals with quantum field theory, whereas the present book treatsonly nonrelativistic quantum mechanics, except for a very brief discussionofquantumfieldtheoryin Sect.20.6.The book begins with a quick introduction to the main ideas of classicaland quantum mechanics. After a brief account in Chap.1 of the historicalorigins of quantum theory, I turn in Chap.2 to a discussion of the neces-sary background from classical mechanics. This includes Newton's equa-tion in varying degrees of generality, along with a discussion of importantphysical quantities such as energy, momentum, and angular momentum,and conditions under which these quantities are“conserved"(i.e., constantalong each solution of Newton's equation).I give a short treatment here
viii Preface attempted to give a reasonably comprehensive treatment of nonrelativistic quantum mechanics, including topics found in typical physics texts (e.g., the harmonic oscillator, the hydrogen atom, and the WKB approximation) as well as more mathematical topics (e.g., quantization schemes, the Stone– von Neumann theorem, and geometric quantization). I have also attempted to minimize the mathematical prerequisites. I do not assume, for example, any prior knowledge of spectral theory or unbounded operators, but provide a full treatment of those topics in Chaps. 6 through 10 of the text. Similarly, I do not assume familiarity with the theory of Lie groups and Lie algebras, but provide a detailed account of those topics in Chap. 16. Whenever possible, I provide full proofs of the stated results. Most of the text will be accessible to graduate students in mathematics who have had a first course in real analysis, covering the basics of L2 spaces and Hilbert spaces. Appendix A reviews some of the results that are used in the main body of the text. In Chaps. 21 and 23, however, I assume knowledge of the theory of manifolds. I have attempted to provide motivation for many of the definitions and proofs in the text, with the result that there is a fair amount of discussion interspersed with the standard definitiontheorem-proof style of mathematical exposition. There are exercises at the end of each chapter, making the book suitable for graduate courses as well as for independent study. In comparison to the present work, classics such as Reed and Simon [34] and Glimm and Jaffe [14], along with the recent book of Schm¨udgen [35], are more focused on the mathematical underpinnings of the theory than on the physical ideas. Hannabuss’s text [22] is fairly accessible to mathematicians, but—despite the word “graduate” in the title of the series— uses an undergraduate level of mathematics. The recent book of Takhtajan [39], meanwhile, has an expository bent to it, but provides less physical motivation and is less self-contained than the present book. Whereas, for example, Takhtajan begins with Lagrangian and Hamiltonian mechanics on manifolds, I begin with “low-tech” classical mechanics on the real line. Similarly, Takhtajan assumes knowledge of unbounded operators and Lie groups, while I provide substantial expositions of both of those subjects. Finally, there is the work of Folland [13], which I highly recommend, but which deals with quantum field theory, whereas the present book treats only nonrelativistic quantum mechanics, except for a very brief discussion of quantum field theory in Sect. 20.6. The book begins with a quick introduction to the main ideas of classical and quantum mechanics. After a brief account in Chap. 1 of the historical origins of quantum theory, I turn in Chap. 2 to a discussion of the necessary background from classical mechanics. This includes Newton’s equation in varying degrees of generality, along with a discussion of important physical quantities such as energy, momentum, and angular momentum, and conditions under which these quantities are “conserved” (i.e., constant along each solution of Newton’s equation). I give a short treatment here