Sökning: "Eigenvalues problem."
Visar resultat 1 - 5 av 48 avhandlingar innehållade orden Eigenvalues problem..
1. Some new results concerning general weighted regular Sturm-Liouville problems
Sammanfattning : In this PhD thesis we study some weighted regular Sturm-Liouville problems in which the weight function takes on both positive and negative signs in an appropriate interval [a,b]. With such problems there is the possible existence of non-real eigenvalues, unlike in the definite case (i.e. LÄS MER
2. Bound states and resonances in three-body system
Sammanfattning : The quantum three-body problem plays an important role in different branches of the modern physics. In the nuclear, atomic and molecular physics there exist a number of systems whose behaviour is naturally described in this framework. LÄS MER
3. The Dirac Equation: Numerical and Asymptotic Analysis
Sammanfattning : The thesis consists of three parts, although each part belongs to a specific subject area in mathematics, they are considered as subfields of the perturbation theory. The main objective of the presented work is the study of the Dirac operator; the first part concerns the treatment of the spurious eigenvalues in the computation of the discrete spectrum. LÄS MER
4. Resolvent Estimates and Bounds on Eigenvalues for Schrödinger and Dirac Operators
Sammanfattning : This thesis concerns the spectral theory of Schrödinger and Dirac operators. The main results relate to the problems of estimating perturbed eigenvalues. The thesis is based on four papers.The first paper focuses on the problem of localization of perturbed eigenvalues for multidimensional Schrödinger operators. LÄS MER
5. Extremal eigenvalues and geometry of quantum graphs
Sammanfattning : This thesis consists of four papers concerning topics in the spectral theory of quantum graphs, which are differential operators on metric graphs.In paper I we present a family of graphs with an arbitrary number of cycles for which a certain eigenvalue upper estimate is sharp. LÄS MER