This textbook provides a modern account of the theory of unbounded selfadjoint operators on Hilbert spaces and their spectral theory, with emphasis on applications in mathematical physics (Schrödinger operators) and analysis (Dirichlet and Neumann Laplacians, SturmLiouville operators, and the Hamburger moment problem). The new edition has been thoroughly revised and updated and features an extensive treatment of the selfadjoint extension theory of symmetric operators. In addition, a number of advanced special topics are presented at the textbook level, accompanied by numerous illustrative examples and exercises.

The main themes of the book are:

• Basics of unbounded operators and fundamental selfadjointness criteria
• Spectral integrals, spectral theorems, and functional calculus for selfadjoint and normal operators
• Perturbations of selfadjointness and of the spectra of selfadjoint operators
• Forms and operators
• Boundary triplets
• The Krein transform and the KreinVishikBirman theory of positive selfadjoint extensions
  With several updates and additions, this edition further enhances an established standard reference and accessible entry point to the subject.

Treats unbounded self-adjoint operators with emphasis on applications in mathematical physics Introduces several important topics not usually covered in textbooks The new edition includes additional advanced topics on unbounded operators

Autorentext

Konrad Schmüdgen is an emeritus professor at the Mathematical Institute of Leipzig University. His expertise is in operator theory, unbounded operator algebras, quantum groups and real algebraic geometry. He has authored several books, including the monograph with A. Klimyk on Quantum Groups and their Representations (1997) and the Graduate Texts in Mathematics The Moment Problem (2017) and An Invitation to Unbounded Representations of ∗-Algebras on Hilbert Space (2020).

Klappentext

This textbook provides a modern account of the theory of unbounded self adjoint operators on Hilbert spaces and their spectral theory, with emphasis on applications in mathematical physics (Schrödinger operators) and analysis (Dirichlet and Neumann Laplacians, Sturm–Liouville operators, and the Hamburger moment problem). The new edition has been thoroughly revised and updated and features an extensive treatment of the self adjoint extension theory of symmetric operators. In addition, a number of advanced special topics are presented at the textbook level, accompanied by numerous illustrative examples and exercises.

The main themes of the book are:

• Basics of unbounded operators and fundamental self adjointness criteria
• Spectral integrals, spectral theorems, and functional calculus for self adjoint and normal operators
• Perturbations of self adjointness and of the spectra of self adjoint operators
• Forms and operators
• Boundary triplets
• The Krein transform and the Krein–Vishik–Birman theory of positive self adjoint extensions
  With several updates and additions, this edition further enhances an established standard reference and accessible entry point to the subject.

Inhalt

Part I. Basics of Closed Operators.- Chapter 1. Closed and Adjoint Operators.- Chapter 2. The Spectrum of a Closed Operator.- Chapter 3. Some Classes of Unbounded Operators.- Part II. Spectral Theory.- Chapter 4. Spectral Measures and Spectral Integrals.- Chapter 5. Spectral Decomposition of Self-Adjoint and Normal Operators.- Part III. Special Topics.- Chapter 6. One-Parameter Groups and Semigroups of Operators.- Chapter 7. Miscellanea.- Part IV. Perturbations of Self-Adjointness and Spectra.- Chapter 8. Perturbations of Self-Adjoint Operators.- Chapter 9. Trace Class Perturbations of Spectra of Self-Adjoint Operators.- Part V. Forms and Operators.- Chapter 10. Semibounded Forms and Self-Adjoint Operators.- Chapter 11. Sectorial Forms and m -Sectorial Operators.- Chapter 12. Discrete Spectra of Self-Adjoint Operators.- Part VI. Self-Adjoint Extension Theory of Symmetric Operators.- Chapter 13. Self-Adjoint Extensions: Cayley Transform and Krein Transform.- Chapter 14. Self-Adjoint Extensions: Boundary Triplets.- Chapter 15. SturmLiouville Operators.- Chapter 16. The One-Dimensional Hamburger Moment Problem.